Altair 4XR Professional Multigas Detector with Bluetooth, manufactured by MSA, for detecting Oxygen, Carbon Monoxide, Hydrogen Sulfide, and LEL. The MSA Altair 4XR is the second generation of Altair 4 multigas detectors. New MSA XCell Sensors have a longer life and higher performance and an End of Sensor Life Warning in the form of a heart icon that indicates when the sensor is nearing the end of its life. Improved buttons are softer, larger and easier to press. Embedded microelectronics provide greater stability and performance and because it’s extremely durable it can survive a 20 ft. drop. Excellent condition, New in box, has never been used. I have 3 of these for sale.The lowest price I could find for this model is $840.00 each. If you buy 1 the price is $250.00, If you want to buy 2 of them the price is $475.00 for both, if you buy all 3 of them the price is $700.00 for all three.