ALTAIR 4XR Multigas Detector, (LEL, O2, H2S & CO), Charcoal case, North American charger Outfitted with rapid-response MSA XCell® sensors, the ALTAIR 4XR Gas Detector is the toughest 4-gas monitor on the market and is backed by a 4-year warranty. The ALTAIR 4XR can also provide real-time incident awareness to team members, supervisors, safety managers and others when paired with the MSA ALTAIR Connect app via a Bluetooth® wireless connection.