Oceanic OCi Wrist Wireless Air-Integrated Dive Computer Complete Powered by Oceanic's Exclusive Dual Algorithm&#153; - Your choice between Pelagic DSAT (Spencer/Powell data basis) or Pelagic Z+ (Buhlmann ZHL-16C data basis) Wireless Air Integrated Technology Advanced Digital Compass with North, Reference, Auto Home, and Declination Adjustment (see NOAA's NGDC geomagnetic chart) Free and Tech Free dive modes Multiple Transmitter Capability & switch between 4 independent transmitters, with up to 4 nitrox mixes to 21-100% O2