Gas monitors are not only expensive to buy, but also expensive to run. Every 6 months you are required to have the unit calibrated at a cost, plus most units come only with a 2 year warranty, so when a sensor expires you are up for the cost to replace it. This gas monitor kit from MSA includes everything you need to calibrate the unit yourself, plus the Altair 4X comes with a 5 year warranty covering all sensors. if you are making a purchase for long term use, then this should be your choice. Some companies insist on daily bump testing. The Altair 4X actually indicates on the main screen that the unit has been bumped within the last 24 hours. Plus the Altair is waterproof and dustproof. The following text describes the unit in more detail.
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, O₂, CO, H₂S, SO₂ and NO₂. 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 th