Technical Dive Computers
Many divers want their dive computer to be able to grow with them, while they progress their diving. Almost all recreational dive computers have a Nitrox mode nowadays and a lot of them can even dive mixed gas, so you can switch between tanks with different gas mixes in them during your dive, which can be useful when you're doing a decompression stop on a tank with a higher oxygen percentage!
When you're looking for computers that can take you even further than that, you look at computers that are made for the technical diving market, such as the incredible Shearwater Perdix with its rec, tec, open circuit and closed circuit modes and high resolution display!
It's predecessor, the Shearwater Petrel 2 has the same modes and a bit more of an industrial look and feel to it, just about 30% less battery power than the new Perdix!