Colour Screen Scuba Diving Computers have a colour display so all of the information shown on the face is colour-coded. Most have fixed colour ranges based on a traffic light system so you know when information turns yellow and red you're reaching a limit. Having key information change colour underwater naturally draws your eyes to it that you may not have noticed on a traditional display. Some dive computers can be customised so you can pick and choose the colours of different information. Colour screen computers illuminate themselves so you don't have to press a button to see the screen in the dark. The constant backlight can reduce the battery life so many have user changeable batteries that are quick and easy to swap or rechargeable batteries built in.