Compatible with Smart Air and Quad Air. Battery type: CR123A, user-replaceable battery. LED colour indicates the remaining air pressure to one's buddy. At the moment the block transmitter is pressurised, if a pressure of 180 bars or more is detected, the LED flashes GREEN 10 times at 4 second intervals. To save battery power, the LED goes off after the surface check.It remains off until a pressure of 100 bar is reached (warning of half pressure). At this point, it flashes YELLOW every 4 seconds. Once the block pressure reaches 50 bar, the LED flashes RED every second (block reserve). Compatible Mares Quad Air and Mares Smart Air EN 250:2014 certified at 300 bars Battery type: CR123A, user replaceable Permanent pairing. The item "Mares Led Tank Dive Computer Probe Compatible With Smart Air And Quad Air" is in sale since Friday, April 16, 2021. This item is in the category "Sporting Goods\Water Sports\Scuba & Snorkeling\Dive Computers". The seller is "outdoorbestforyou" and is located in Alytus. This item can be shipped worldwide.