The Seac Guru Dive Computer is a watch sized dive computer that is packed full of features for any diver. The full Dot-Matrix screen is easy to read & underst&. Inside is a rechargeable battery & you download upgrades via the same USB (Universal Serial Bus) cable when connected to your desktop computer. Dive Modes The Guru has algorithms for Air, Nitrox & Freediving as well as a Gauge mode when you just need it to be a bottom timer. Specifications 2 Gases Buhlmann ZHL-16B (6 level adjustment) 80x 80 Dot Matrix Rechargeable Li-Ion Battery (~40hr dive mode) Mineral Glass Silicone Strap Wireless Transmitter Compatible (not included) Max Depth 150m Automatic Altitude Fresh/ Salt Water Compass Fitness Functions Backlight ~160hr logbook Included: USB (Universal Serial Bus) cable extension strap