The MSA 10106725 is a genuine XCell CO/H2S "Two-tox" replacement sensor — a single electrochemical module that detects both carbon monoxide (CO) and hydrogen sulfide (H2S) at once, occupying one sensor slot instead of two. It measures CO from 0–1999 ppm and H2S from 0–200 ppm (1 ppm resolution each), and fits MSA ALTAIR 4X, 4XR, and 5X gas monitors. It is sold at Industrial Safety Products with free shipping.

The MSA 10106725 XCell CO/H2S Two-tox sensor fits the MSA ALTAIR 4X, ALTAIR 4XR, and ALTAIR 5X gas monitors. Confirm your instrument is one of these models before ordering, since it is a model-specific replacement sensor.

The MSA 10106725 XCell CO/H2S sensor measures carbon monoxide (CO) from 0 to 1999 ppm and hydrogen sulfide (H2S) from 0 to 200 ppm, both at 1 ppm resolution. Its factory alarm setpoints span 7–1700 ppm for CO and 2–175 ppm for H2S, reporting both gases from a single Two-tox module.

Very fast — the MSA 10106725 has a typical response time of t(90) under 15 seconds for both the CO and H2S channels, meaning it reaches 90% of the true reading in less than 15 seconds. This industry-leading response helps workers react quickly when gas is present.

The MSA 10106725 XCell CO/H2S sensor has a typical life of more than 4 years, which means fewer sensor replacements over the instrument's service life. It also carries a 3-year warranty. XCell sensors are built for long-term stability, so readings stay reliable across the sensor's life.

No — virtually not. The MSA 10106725 is a Two-tox sensor with a partitioned design, and MSA states it has "virtually no cross-channel interference" between the CO and H2S partitions. That means the two gas readings stay accurate and independent even though they come from one combined module, unlike older designs where one toxic channel could bleed into the other.

Yes — like all electrochemical CO sensors, it has cross-sensitivities. Hydrogen (H2) produces roughly a 2:1 (about 48%) response on the CO channel, so MSA does not recommend using the CO sensor to detect hydrogen — use the LEL/combustible sensor instead. Alcohols and other VOCs (methanol, ethanol, IPA) can also cause a delayed positive CO response. Knowing these interferences helps you interpret readings correctly in atmospheres where those gases are present.

Yes. MSA XCell sensors use an electrolyte formulation that keeps performing down to –45 °C (–49 °F), well below the roughly –28 °C (–18 °F) freezing point of historic sensor formulations. XCell sensors also use ASIC-based temperature compensation to stabilize readings during rapid temperature swings, making the 10106725 suitable for cold-climate and outdoor work.

Yes. The MSA 10106725 is a genuine MSA XCell CO/H2S Two-tox replacement sensor (SKU 10106725-MSA), available at Industrial Safety Products (industrialsafetyproducts.com) with free shipping. It is the correct combination CO/H2S sensor for MSA ALTAIR 4X, 4XR, and 5X monitors.

Because it combines both toxic channels into one module. The MSA 10106725 detects CO (0–1999 ppm) and H2S (0–200 ppm) — the two most common toxic hazards in confined-space and industrial work — from a single Two-tox sensor that uses one slot with virtually no cross-channel interference. That means one part number to stock and replace, freed space in the instrument for other sensors (LEL, O2), and MSA's under-15-second response and greater-than-4-year life on both gases.