A scuba diving computer is a great addition to any kit and due to the fact that it allows you to have a safer dive than the traditional table method it's becoming a essential piece of equipment for most divers. Like most items of equipment there is a wide range of choice available on the market to suit all kinds of budgets. Dive computers generally come in two different types; console computers and wrist computers. Both have their advantages and dis advantages so it best to choose the one that suits you and the nature of your dives. If choosing a wrist computer you will still require a seperate submersible pressure gauge (SPG) and a compass. If you opt for a console computer it will be mounted within an instrument console, sometimes with other instruments and many have a matching compass available that can be attached. Most console computers can be placed into the depth gauge pocket whereas air integrated computers connect to your regulator first stage using a high pressure hose so they can check your air supply, therefore a seperate pressure gaugue is not needed. Another type of computer is a Nitrox which generally is used for air or Nitrox mixtures which are 40% or richer. These types of computers allow you to enter the Nitrox mix resulting in decompression limits being auotomatically calculated for the breathing gas that's used. A lot of the newer dive computers have Nitrox programming built in.