Some models have a Compass mounted. Dive Computers go into a sleep mode or turn off if not used within a certain period of time. Most of today's models allows for the diver to change his own batteries. Computers can be mounted in a console, on the wrist in a wrist boot, or on the hose in a hose boot. How a computer is mounted is dependent on the divers preference and the computer's configuration.
Some models have a pressure gauge integrated into the unit.
These computers are able to display the amount of remaining air and calculate how long your air will last based on current breathing rate. Nitrox computers offer all the same features as the air computers, but also allow the use of Oxygen Enriched Air. Once a diver's nitrox is programmed in the computer, decompression limits are adjusted accordingly. Warnings communicate to the diver nitrogen loading and oxygen limits for the present nitrox at any given point of time during the dive. It is wise to realize that today's computers although very good are all based on mathematical models and are therefore not a perfect solution .