Orion™ Multigas Detector is a low-cost, reliable and easy-to-use portable instrument for detecting the presence of O2, H2S, CO and combustible gas. It will stand up to the roughest handling in even the toughest environments. Orion™ Multigas Detector Features One-Button Calibration, Long-Life Battery, Carbon-Filled Nylon Case, Large Easy-to-Read Display Durable Sensors and Link™ Software. It is available in 3 gas-(LEL/CO/O2) and 4 gas-(LEL/CO/O2/H2S).