TopTes Guard-101 vs 156 vs 863Pro: Which 4-Gas Monitor?
TopTes Guard-101 vs 156 vs 863Pro — which 4-gas?
Short answer: All three read O2/LEL/CO/H2S. Pick the Guard-101 for lowest cost, the Guard-156 for fast 0.5s response, or the Guard-863Pro for a color screen, USB data export and a 5-year O2 sensor.
TopTes makes three popular value-tier 4-gas monitors. They share the same gas set, so the choice is about features and budget. All are in Portable Gas Detectors.
At a glance
| Spec | Guard-101 | Guard-156 | Guard-863Pro |
|---|---|---|---|
| Gases | O2/LEL/CO/H2S | O2/LEL/CO/H2S | O2/LEL/CO/H2S |
| Display | LCD | LCD | TFT color |
| Battery | 14 h | Long-life | 18 h |
| Response | Standard | 0.5 s | Standard |
| Data export | No | No | USB |
| O2 sensor | Standard | Standard | 5-year |
| Street price | ~$106 | ~$127 | ~$170 |
Guard-101
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Guard-156
VIEW GUARD-156 →CHECK PRICE ON AMAZON →As an Amazon Associate, WC Safety earns from qualifying purchases.
Guard-863Pro
VIEW GUARD-863PRO →CHECK PRICE ON AMAZON →As an Amazon Associate, WC Safety earns from qualifying purchases.
Which should you buy?
- Choose the Guard-101 for the lowest price and the deepest review base.
- Choose the Guard-156 for fast 0.5-second response in a rugged body.
- Choose the Guard-863Pro for a color screen, USB data export and a 5-year O2 sensor.
How to pick
The Guard-101 is the value workhorse; the Guard-156 adds faster response and a dust/explosion-proof build; the Guard-863Pro is the feature leader with a color display, exportable logs and a longer-life oxygen sensor that lowers running cost. For a NIST-certified alternative, compare the Forensics Mini 4 Gas. Calibrate all with gas from Calibration & Accessories.
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Frequently asked questions
Do all three detect the same gases?
Yes — O2, LEL combustibles, CO and H2S.
Which is cheapest?
The Guard-101, the lowest-priced and most-reviewed of the three.
Which has a color screen?
The Guard-863Pro, with a TFT color display.
Which has the fastest response?
The Guard-156, at about 0.5 seconds.
Which exports data?
Only the Guard-863Pro, via USB.
Which has the longest-life O2 sensor?
The Guard-863Pro, with a 5-year oxygen sensor.
Are they NIST calibrated?
They are factory-set; for a NIST certificate consider the Forensics Mini 4 Gas.
Which battery lasts longest?
The Guard-863Pro at up to 18 hours; the Guard-101 runs about 14 hours.
Which for confined-space entry?
Any of them for monitoring; add a pump unit for pre-entry sampling.
Do they detect VOCs?
No — use a VOC detector for VOCs.
Disclosure & how we compare. WC Safety is an independent industrial safety-equipment retailer. Comparisons are based on manufacturer specifications and intended use, framed against OSHA 29 CFR 1910.146 and OSHA PELs. We participate in the Amazon Associates Program (tag wcsafety04-20) and earn on qualifying purchases; that does not change our recommendations. Buyer guidance only, not medical, legal or regulatory advice.
By Steven Eaton, WC Safety Editorial · · industrial gas-detection desk.