This is the Mares Quad 2 Multi-gas Capable Scuba Diving Computer Features: Bühlmann ZH-L16C algorithm with customizable Gradient Factors Alternate Gradient Factors and Ceil-Con decompression Air, Nitrox, Trimix, Bottom Timer Clear segmented display made using chip-on-glass technology Bottom Timer mode with resettable Average Depth and Stopwatch Decompression dive planner with additional Surface Interval function Logbook capacity: 100 hours of Dive Profile at a 5-second Sampling Rate User-replaceable battery (CR 2450) with a long battery life of 100 dives Integrated Bluetooth for direct connection to a Smart Device Underwater menu allows certain Settings to be changed during the Dive TTR - Time to Reserve - time that a Diver can spend at the current Depth before reaching the Tank Reserve Four Buttons for intuitive User Interface plus Quick Commands Altitude automatically adapted by sensing the Ambient Pressure every 20 seconds, even when turned off Firmware update via the Mares app Max Displayed Depth 150 m / 492 ft Memory capacity 100 hr Profile Sampling Rates 5 s Stopwatch true The Mares Quad 2 is the ultimate scuba diving computer for experts. Features like customizable Gradient Factors, alternate decompression options, and various gas capabilities make it a versatile tool for any dive. Its advanced technology, long battery life, and direct connection to a smart device make it a must-have for serious divers.