Moldex Rockets 6404 Corded Reusable Earplugs NRR 27 Bagged 50 Pairs Review (2026)

The Reusable Earplug That Punches Above Its Price: Rockets 6404 Tested in Real-World Noise

Moldex Rockets 6404 Corded Reusable Earplugs NRR 27 Bagged 50 Pairs Review (2026)

By Steven Eaton, WC Safety | Updated June 2026

Most disposable earplugs get tossed after a single shift. The Moldex Rockets 6404 takes a different approach: a triple-flange, corded, reusable earplug rated NRR 27 dB that workers can wear all day, wash at night, and reuse across multiple shifts. That proposition makes sense for operations where hearing conservation budgets are tight and earplug accountability is high.

This review examines the Rockets 6404 against verified specs from Moldex, the requirements of ANSI S3.19 and OSHA 29 CFR 1910.95, and the practical realities of corded reusable earplug use in manufacturing, construction, and utilities environments. No manufacturer marketing claims are included unless supported by the physical product design.

If you manage a workplace hearing conservation program or you are selecting earplugs for a team, this breakdown covers everything you need to make an informed decision — specs, NRR math, cost-per-use, and how the 6404 stacks up against competing models. For a broader look at the category, see the best earplugs for work guide and the best hearing protection guide.

Who the Moldex Rockets 6404 Is For

The 6404 is purpose-built for workers who move repeatedly between noisy and quieter zones during a shift. Unlike foam earplugs that require full re-insertion after each removal, the triple-flange stem re-seats quickly at the ear canal entrance without deep insertion. That makes the Rockets a practical choice for:

• Manufacturing assemblers who step away from machinery to communicate and return
• Utilities and maintenance crews needing reliable attenuation around generators, compressors, and power tools
• Construction workers operating intermittently in high-noise zones under a OSHA hearing conservation program
• Safety managers issuing bulk PPE across a shift workforce and tracking reuse compliance
• Workers with latex or chemical sensitivities who require a latex-free, PVC-free, and diisocyanate-free hearing protector

If your environment exceeds 100 dBA TWA consistently, the Rockets 6404 alone may not be sufficient. Review the NRR guide to determine whether dual protection is required and how to calculate effective attenuation for your exposure level. You can also explore the full hearing protection collection and the earplugs collection to compare alternatives.

Strengths of the Moldex Rockets 6404

NRR 27 dB: Solid Attenuation for Most Industrial Settings

The Rockets 6404 carries an NRR of 27 dB, tested and rated under ANSI S3.19-1974 — the standard used for all EPA-regulated hearing protector labeling in the United States. Under OSHA's recommended 50% derating factor, real-world effective attenuation is approximately 10 dB. Applied to an 8-hour TWA exposure of 95 dBA, that brings effective worker exposure to roughly 85 dBA — within OSHA's permissible limit under 29 CFR 1910.95.

For environments in the 85 to 100 dBA TWA range, the 6404 provides compliant, single-unit protection when worn correctly. This covers a broad range of industrial operations including metal stamping at moderate distance, packaging machinery, and light construction equipment. Consult the best hearing protection guide for help matching NRR to your specific noise level.

Triple-Flange Design: No Roll-Down Required

Unlike foam earplugs that must be rolled, compressed, and held in place during expansion, the Rockets 6404 uses a triple-flange stem that inserts at the ear canal entrance without deep canal penetration. The worker twists the plug into position — a motion that takes seconds rather than the 20 to 30 second roll-hold cycle of a foam plug.

This matters operationally. Workers who rush insertion on foam plugs often achieve poor attenuation because the plug was not held long enough to expand. The flanged design reduces insertion-error risk and supports more consistent protection across a team. Safety managers auditing PPE compliance will find the flanged plug easier to verify visually — if the stem is seated at the canal entrance, the plug is in the correct position.

Compare this approach with the full reusable vs. disposable earplugs breakdown to understand when each insertion style makes operational sense.

Latex-Free, PVC-Free, Diisocyanate-Free Polymer

Moldex specifies the 6404 material as free of latex, PVC, and diisocyanates. These are the three most common chemical sensitivities in industrial PPE. For workers with Type I latex hypersensitivity or documented PVC sensitization, the material composition reduces exposure risk from daily-worn hearing protection. The antimicrobial compound embedded in the polymer is intended to inhibit microbial growth during multi-shift use — a relevant feature when plugs are cleaned and returned to the same worker across days or weeks.

Corded Design: Retention and Accountability

The standard polymer cord connecting the two earplugs provides retention when the plugs are removed — they hang around the worker's neck rather than being pocketed or set down on a surface. This reduces loss, contamination from environmental surfaces, and the likelihood of leaving hearing protection behind when re-entering a noisy area. For safety managers, the cord also provides a visual compliance indicator: a worker with corded earplugs hanging at their neck has PPE accessible and ready to re-insert.

50-Pair Bulk Bagged: Cost-Effective for Team Issue

The 6404 ships in a 50-pair bulk bag format, which suits industrial purchasing and team-issue programs. When comparing hearing protection costs across a team, the per-pair price of a multi-use plug like the Rockets 6404 — when worn across multiple shifts before replacement — typically undercuts the weekly per-pair cost of disposable foam earplugs. The reusable vs. disposable earplug guide covers this cost comparison in detail. For a broader look at Moldex hearing protection options at different price points, see the best Moldex earplugs guide.

Limitations to Understand Before Buying

Flanged Fit Requires Compatible Canal Anatomy

The triple-flange design works well for workers with typical ear canal diameter and shape. Workers with very narrow, very wide, or unusually curved canals may find the 6404 flanges do not create an adequate acoustic seal, resulting in real-world attenuation below the rated NRR. Foam earplugs conform to a wider range of canal geometries through expansion. If your workforce is large and diverse, pilot testing across a sample group before bulk purchase is advisable. Browse the full earplugs collection to compare foam and flanged options side by side.

Reuse Requires Active Inspection

The 6404 must be replaced when the flanges stiffen, crack, or permanently deform. In a high-volume workplace, this adds an inspection step that disposable earplugs eliminate entirely. Without a structured replacement protocol, some workers may continue using degraded plugs past their effective service life, reducing actual attenuation without any visible indicator from the outside. A written replacement policy and periodic supervisor checks are necessary to maintain compliance under OSHA 29 CFR 1910.95.

Cord Introduces a Snag Point

In environments with rotating machinery, conveyors, or moving parts at torso height, a cord hanging around the neck creates an entanglement hazard. OSHA 29 CFR 1910.212 addresses machine guarding, and PPE selection should not introduce additional mechanical hazards. In those environments, a cordless earplug or a higher-attenuation alternative such as earmuffs may be more appropriate. Review your site's machine guarding risk assessment before issuing corded PPE near exposed moving machinery.

NRR 27 dB Has a Practical Ceiling

At sustained exposures above 100 dBA TWA, the Rockets 6404 used alone may not achieve sufficient attenuation for an 8-hour shift. NIOSH and OSHA guidance on dual protection — earplug plus earmuff combination — applies at these exposure levels. The combined NRR calculation under OSHA's method adds approximately 5 dB of effective attenuation to the higher-rated device when both are worn. For environments running above 100 dBA, explore the full hearing protection catalog for higher-rated options or dual-protection pairings.

How the Rockets 6404 Compares

The Rockets 6404 sits at NRR 27 dB, lower than the Moldex 6800 SparkPlugs (NRR 33 dB) but serving a similar operational niche — corded reusable protection. The 6404's flanged design is the key differentiator: faster insertion, no compression step, and reduced insertion-error variability. For environments where maximum attenuation is the priority, the 6800 or a high-NRR disposable is the stronger choice. For environments prioritizing quick on/off and chemical material compatibility, the 6404 holds its ground. See the complete Moldex earplug comparison guide for a full catalog breakdown.

Rockets Series: Other Options to Consider

Compatible Accessories and Complementary PPE

The Rockets 6404 is a standalone hearing protector but integrates into a broader PPE program alongside:

• Safety glasses and face shields — the earplug cord sits below the temple of eyewear without interference. Browse the full PPE catalog for compatible eye and face protection.
• Hard hats with earmuff attachments — if noise levels require dual protection, cap-mounted earmuffs can be added above the Rockets 6404 for combined attenuation. See the hearing protection collection for earmuff options.
• Dispenser stations — for the uncorded 6400/6401 variants; the 6404 bulk bag is compatible with bin-style dispensers for team-issue setups.

OSHA 29 CFR 1910.95 and ANSI S3.19: What the NRR Means for Your Program

Under OSHA 29 CFR 1910.95, employers must implement a hearing conservation program when workers are exposed to an 8-hour time-weighted average of 85 dBA or above — the action level. At the permissible exposure limit of 90 dBA TWA, hearing protection must reduce effective exposure below that threshold.

The NRR 27 dB on the Rockets 6404 is measured under ANSI S3.19-1974, the standard governing hearing protector testing in the U.S. OSHA recommends applying a 50% derating to the labeled NRR to account for real-world fit variability: (27 minus 7) divided by 2 equals approximately 10 dB effective attenuation. This is the figure safety professionals should use when determining adequacy of protection for a given noise exposure level.

Applied examples for an 8-hour TWA:

• 85 dBA TWA minus 10 dB = 75 dBA effective — compliant
• 95 dBA TWA minus 10 dB = 85 dBA effective — compliant
• 100 dBA TWA minus 10 dB = 90 dBA effective — at the PEL; dual protection should be evaluated
• 105 dBA TWA minus 10 dB = 95 dBA effective — exceeds PEL; dual protection required

For the full methodology and worked examples, see the NRR hearing protection guide and the hearing conservation program guide.

Total Cost of Ownership: Reusable vs. Disposable Over 90 Days

The Rockets 6404 50-pair bag works out to a per-pair cost that, spread across multi-shift reuse with daily washing, is substantially lower than the per-shift cost of disposable foam earplugs purchased at comparable volume. The breakeven point against disposables typically occurs within the first two weeks of use per pair.

However, the true TCO includes several factors beyond purchase price:

• Inspection labor — time spent checking flanges for stiffening or cracking before each shift
• Replacement rate — pairs that fail inspection must be discarded before reaching their theoretical reuse potential
• Loss rate — cord reduces loss vs. uncorded, but plugs still go missing in high-turnover environments
• Cleaning compliance — workers who skip daily washing reduce the effective service life of each pair

For a full analysis of reusable versus disposable earplug economics in a workplace program context, see the reusable vs. disposable earplugs guide.

Final Verdict

The Moldex Rockets 6404 is a well-specified corded reusable earplug for industrial hearing conservation programs. Its NRR 27 dB covers the majority of manufacturing and construction exposure scenarios up to approximately 100 dBA TWA. The triple-flange insertion method is faster and less error-prone than foam roll-down, the material chemistry eliminates the most common PPE allergens, and the 50-pair bulk format serves team-issue purchasing efficiently.

Its limitations are real but manageable: flanged fit requires compatible anatomy, reuse demands an inspection protocol, and the cord is not appropriate in all mechanical environments. For exposures above 100 dBA TWA, dual protection should be evaluated. For food and pharmaceutical applications, the metal-detectable 6415 is the correct SKU.

For the right application — corded reusable protection in 85 to 100 dBA TWA industrial environments — the Rockets 6404 earns a 4.5/5. It is a reliable, chemically clean, operationally practical earplug that holds up to rigorous shift-use demands. See the best earplugs for work guide and the best hearing protection guide for broader program-level recommendations.

Frequently Asked Questions

What is the NRR of the Moldex Rockets 6404?

The Moldex Rockets 6404 has an NRR of 27 dB, tested under ANSI S3.19-1974. Applying OSHA's recommended 50% derating factor, effective real-world attenuation is approximately 10 dB for program compliance calculations. See the full NRR hearing protection guide for derating methodology.

Are the Moldex Rockets 6404 reusable?

Yes. The 6404 is a reusable earplug. After each use, wash with soap and water and allow to air dry. Replace the pair when the flanges show signs of stiffening, cracking, or permanent deformation that would compromise the acoustic seal.

How do you insert the Moldex Rockets 6404?

Twist the triple-flange stem into the entrance of the ear canal until the outermost flange creates a seal against the canal opening. No foam rolling or deep insertion is required. The flanges seal at the canal entrance rather than deep within the canal.

Are the Rockets 6404 latex-free?

Yes. Moldex specifies the 6404 material as latex-free, PVC-free, and diisocyanate-free — making them suitable for workers with these chemical sensitivities.

What is the difference between the Moldex 6400 and 6404?

The 6404 is corded — the two earplugs are connected by a polymer cord. The 6400 is the uncorded version of the same triple-flange Rockets design. Both carry NRR 27 dB. Choose the 6404 when cord retention is beneficial; choose the 6400 when the cord creates a snag or entanglement hazard.

What noise levels do the Rockets 6404 protect against?

With an effective attenuation of approximately 10 dB after OSHA 50% derating, the Rockets 6404 provides compliant protection for 8-hour TWA exposures up to roughly 100 dBA. Above that level, dual protection — earplug plus earmuff — should be evaluated per OSHA guidance.

Are the Moldex Rockets 6404 metal-detectable?

No. The standard 6404 is not metal-detectable. For food manufacturing or pharmaceutical environments requiring metal-detectable PPE, the Moldex 6415 is the correct variant.

Can I wash the Rockets 6404 earplugs?

Yes. Wash with mild soap and warm water. Rinse thoroughly and air dry completely before reuse. Do not expose to solvents or harsh cleaning chemicals, which can degrade the polymer flanges and reduce effective attenuation.

How many pairs are included in the 6404 bag?

The Moldex Rockets 6404 in the bagged format includes 50 pairs, suited for bulk issue in workplace hearing conservation programs.

Do the Moldex Rockets 6404 comply with OSHA 29 CFR 1910.95?

The 6404 is an NRR-labeled hearing protector tested under ANSI S3.19-1974, which satisfies OSHA 29 CFR 1910.95 requirements for hearing protector selection when the NRR is sufficient to reduce worker exposure below permissible limits. Compliance depends on the specific noise exposure level at your site and correct application of the derating calculation.

How does the Rockets 6404 compare to foam earplugs?

The 6404's flanged design inserts faster and without the roll-compress-hold step required by foam plugs, reducing insertion error. However, foam earplugs generally conform to a wider range of canal shapes and typically achieve higher NRR ratings up to NRR 33 dB. See the best foam earplugs guide for a detailed comparison and the reusable vs. disposable guide for operational trade-offs.

What is the antimicrobial compound in the Rockets 6404?

Moldex embeds an antimicrobial agent into the earplug polymer to inhibit microbial growth during multi-shift use. The specific antimicrobial chemistry is not publicly disclosed by Moldex beyond the material claim. It is integrated into the material rather than applied as a surface coating.

Are the Rockets 6404 suitable for food manufacturing?

Not as specified. The standard 6404 is not metal-detectable, which is typically required in food manufacturing environments to comply with product contamination protocols. Use the Moldex 6415 metal-detectable variant instead.

What is the best earplug for an OSHA hearing conservation program?

The right earplug depends on noise exposure level, workforce anatomy variability, insertion reliability, and operational factors including cord requirements. The best earplugs for work guide covers the key selection criteria in detail. The Rockets 6404 is a strong candidate for 85 to 100 dBA TWA corded reusable applications.

How does the NRR 27 dB compare to other Moldex earplugs?

NRR 27 dB is mid-range within the Moldex catalog. Moldex offers plugs from NRR 27 dB — Rockets — up to NRR 33 dB — SparkPlugs and Purafit. For the highest attenuation in the Moldex range, see the best Moldex earplugs guide.

Can the Rockets 6404 be worn under a hard hat?

Yes. The triple-flange stem sits at the ear canal entrance and the cord hangs at the neck — neither interferes with hard hat fit or brim position. The 6404 is compatible with standard hard hat use in construction and industrial environments.

Where can I learn more about hearing protection selection?

The best hearing protection guide covers earplugs, earmuffs, and dual-protection setups. The hearing conservation program guide details OSHA compliance requirements and program structure for workplace safety managers. The full hearing protection collection lists all available products.

Is the Moldex Rockets 6404 appropriate for construction sites?

Yes, provided the noise exposure at your site does not consistently exceed 100 dBA TWA and cord entanglement hazards are not present near the worker's task area. For higher-exposure construction environments, evaluate higher-NRR options from the hearing protection collection or consider dual protection configurations.

About the Author

Steven Eaton is the founder and lead editor of WC Safety, a workplace personal protective equipment retailer. Steven reviews and selects PPE based on regulatory standards compliance, manufacturer specifications, and operational fit for industrial and construction environments. All product reviews are written in alignment with WC Safety's editorial standards for factual accuracy and OSHA compliance context.

Reviewed June 2026 | Next scheduled review: December 2026

Review Methodology

This review was produced using the following sources:

• Moldex published product specifications for SKU 6404 — NRR, material composition, design, and maintenance requirements
• ANSI S3.19-1974 — NRR testing standard for hearing protector labeling
• OSHA 29 CFR 1910.95 — occupational noise exposure permissible limits and hearing conservation program requirements
• OSHA 50% NRR derating methodology for real-world effective attenuation calculation

No independent field attenuation testing was conducted. No user reviews or unverified third-party claims are included. Pricing data reflects publicly available Amazon listing data at time of review.