The ALTAIR 4X is an extremely durable Multigas Detector that simultaneously measures up to four gases from a wide range of XCell(R) sensor options including combustible gases, O , CO, H S, SO and NO . The ALTAIR 4X Detector surpasses industry standards in several crucial areas. Its four-year sensor life is 60% longer than the industry average, while its 24-hour run time exceeds the industry average by 71%. This versatile portable detector is a perfect match for industries ranging from fire fighting to welding, and its digital sensor output makes it less likely to suffer from RF interference. The unit features exclusive MotionAlert , which lets others know if the user has become immobile, and InstantAlert , a manual alarm that alerts others of potentially dangerous situations. This rugged unit is designed to withstand a drop of up to 20 ft (6m) and uses less than half as much calibration gas as the industry average.