You can track your dives using dive tables, a depth gauge and diving watch, but most scuba divers use a diving computer it’s easier. A diving computer provides the real-time dive information you need to dive well.
A diving computer takes depth and time information and applies it to a decompression model to track the dissolved nitrogen in your body during a dive. Your computer continuously tells you how much dive time you safely have remaining. Your computer combines a depth gauge, timer and sometimes a submersible pressure gauge (SPG) into a single, useful instrument.