When it comes to personal gas detection in hazardous environments, the MSA ALTAIR 4XR and MSA ALTAIR io 4 are two of the most reliable devices on the market. Both are 4-gas detectors designed to monitor the presence of LEL (Lower Explosive Limit), O2 (Oxygen), CO (Carbon Monoxide), and H2S (Hydrogen Sulfide). Despite their similar core functionalities, these devices differ in several key areas, including battery life, weight, advanced connectivity features, and more. This comprehensive guid …