A rugged, full-function technical dive computer, the Shearwater Petrel accommodates both open circuit and closed circuit diving. In addition to air, divers can program up to five nitrox or tri-mix gasses for each. A two-button interface and intuitive menu system simplify programming and adjustments during the dive. It’s available in a “Standalone” version or EXT, which includes a Fischer connector for receiving O2 data.