Moldex 6604 SparkPlugs Cordless Earplugs — NRR 33 (Metal-Detectable)

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Read our hands-on Moldex 6604 SparkPlugs review for field-tested buyer notes.

Moldex 6604 SparkPlugs Cordless Earplugs Overview

The Moldex 6604 SparkPlugs Cordless Earplugs are cordless single-use foam ear plugs from Moldex, rated NRR 33 dB. With no cord to catch or snag, they keep a low profile for tight and confined spaces — the most economical choice for high-volume single-use. They are metal-detectable — a metal element lets food-line detectors catch a lost plug, so they suit food and pharma production. Start with our hearing-protection guide and what NRR means, then confirm the noise level you’re protecting against.

The Moldex 6604 SparkPlugs belong to the cordless ear plugs range and the NRR 33 ear plugs group. They are single-use (replace when soiled or no longer springy); for the trade-offs see foam vs reusable ear plugs.

What NRR 33 dB Means

NRR is a laboratory rating; NIOSH suggests derating it for real-world use. Here is how NRR 33 dB lines up with common environments (always confirm with a noise survey):

Who Should Buy the Moldex 6604 SparkPlugs?

Buy them if you want single-use foam hearing protection in a low-profile uncorded design at NRR 33 dB that's also detectable on food lines. Consider another plug if you need a different level or style: compare 6430 Alphas, 6450 Jetz, 6598 BattlePlugs. For the highest ratings see highest-NRR ear plugs.

Hearing protection only works when worn correctly for the full exposure. The NRR is a laboratory rating; real-world attenuation is typically lower, so OSHA and NIOSH recommend derating it when estimating protection. For very high noise — or whenever earplugs alone can’t bring exposure under about 85 dBA — wear them with earmuffs (dual protection). The Moldex 6604 SparkPlugs reduces noise; it does not eliminate it or protect against non-noise hazards.

Best Applications

Industrial & construction noise

Power tools, plants and construction work at sustained high noise suit a low-profile uncorded NRR 33 plug that won’t snag in tight spaces.

Food & pharma production

Detectable-loss control makes these a fit for food-safe production lines.

Pros & Cons

Moldex 6604 SparkPlugs vs Other Corded Ear Plugs

Moldex 6604 SparkPlugs vs the Alternatives

How they compare to close options:

• 6604 SparkPlugs vs 6430 Alphas: 6430 Alphas is NRR 27 (reusable flanged); the 6604 SparkPlugs is NRR 33 (single-use foam).
• 6604 SparkPlugs vs 6450 Jetz: 6450 Jetz is NRR 27 (reusable flanged); the 6604 SparkPlugs is NRR 33 (single-use foam).
• 6604 SparkPlugs vs 6598 BattlePlugs: 6598 BattlePlugs is NRR 24 (dual-mode); the 6604 SparkPlugs is NRR 33 (single-use foam).

Moldex 6604 SparkPlugs Quick Answers

Are cordless plugs less protective than corded?

No — same plug body and seal means the same NRR; a cord is only for retention.

Are the Moldex 6604 SparkPlugs washable?

No — single-use foam; replace when soiled.

Plugs or muffs?

Both for the highest noise; see ear plugs vs ear muffs.

Moldex 6604 SparkPlugs Specifications

Fit & Sizing

The Moldex 6604 SparkPlugs are single-use foam cordless ear plugs. To fit them, roll them down between your fingers, pull the ear up and back, and insert — they expand to seal the canal — the seal, not just the NRR number, is what protects your hearing. They are one size fits most and single-use (replace when soiled or no longer springy). Browse more options in foam ear plugs, the full cordless ear plugs range, or all hearing protection. For detectable-loss control, see metal-detectable ear plugs.

Helpful Hearing-Protection Guides

• Best hearing protection
• What NRR (noise reduction rating) means
• Foam vs reusable ear plugs
• Corded vs cordless ear plugs
• Highest-NRR ear plugs
• Ear plugs vs ear muffs
• OSHA hearing conservation (1910.95)

Moldex 6604 SparkPlugs Frequently Asked Questions

What is the NRR of the Moldex 6604 SparkPlugs?

The Moldex 6604 SparkPlugs are rated NRR 33 dB (EPA-labeled per ANSI S3.19). Real-world protection is usually lower, so NIOSH recommends derating the NRR when estimating exposure.

Are the Moldex 6604 SparkPlugs cordless?

Yes — uncorded for a low-profile fit with no cord to catch, and the most economical option for high-volume single-use.

Are the Moldex 6604 SparkPlugs reusable or single-use?

They are single-use (replace when soiled or no longer springy).

How do I insert the Moldex 6604 SparkPlugs?

To fit them, roll them down between your fingers, pull the ear up and back, and insert — they expand to seal the canal. A proper seal is what delivers the rated protection.

Can I wash the Moldex 6604 SparkPlugs?

They are single-use foam — replace rather than wash once soiled or no longer expanding.

Are the Moldex 6604 SparkPlugs metal-detectable?

Yes — an embedded metal element lets production-line detectors find a dropped plug, so they suit food and pharma lines.

What size are the Moldex 6604 SparkPlugs?

They are one size fits most.

What noise levels suit NRR 33?

NRR 33 dB suits common industrial noise once derated; for very high or impulse noise, add earmuffs for dual protection. See what NRR means.

Are cordless ear plugs less protective than corded?

No. A cord is only for retention; an uncorded plug with the same body and seal delivers the same NRR.

Are the Moldex 6604 SparkPlugs NIOSH/EPA labeled?

Yes — NRR 33 dB is EPA-labeled under ANSI S3.19. WC Safety sells authentic Moldex hearing protection through legitimate channels.

Can I buy the Moldex 6604 SparkPlugs in bulk or by the case?

Yes. Use the Request a Quote option for case and dispenser pricing on volume orders.

Should I choose ear plugs or ear muffs?

Plugs suit tight spaces, heat and all-day wear; muffs are faster on/off. Many high-noise jobs use both — see ear plugs vs ear muffs.