This is a full-function watch and a nitrox computer that will make your head spin with its multi-gas capabilities. Built into the Atom are a slew of user-selectable functions —everything from water-contact activation to turn-around-pressure alarms. Packaging With its tough black exterior, it looks like an oversize watch, but it has serious computing power. Four push buttons are used for programming, and the display is partitioned into three segments, the largest at the bottom for displaying critical dive data. A small LED warning light hangs off the side of the case at 9 o'clock. Core functions Not only will the Atom accommodate three nitrox mixes, but it will also function with up to three wireless transmitters, so the diver can receive tank-pressure data each time a breathing-mix change is made. If you program the Atom for a particular nitrox mix, the computer will default back to an FO2 of 50 percent 10 minutes after surfacing from a dive; however, this function can be turned off. When it comes to dive planning, the Atom will give dive times based solely on the first breathing mix, though it will, of course, give dive times based on the selected mix during an actual dive. Gas switches cannot be made on the surface as the computer always starts a dive on the first mix. Switching gases during the dive is done manually and can be performed with or without the use of a transmitter on all tanks. If a gas switch would violate a pre-set PO2 limit , the Atom sounds a warning but will allow the switch — a nice function if you have a shortage of primary breathing gas from an equipment failure or from sharing air with a buddy. Divers who want a more conservative profile have two options with the Atom. First, a small graphic at the top left of the screen gives a visual representation of nitrogen loading, with a full graph equal to the diver's no-decompression limit. Keeping the graph one or two bars away from full is a great way to be conservative. However, it also has a user-selectable conservatism that, when activated, calculates dive times by assuming the next-highest altitude bracket, thus limiting bottom times. For ascent rates, the Atom allows 60 fpm below 60 feet and 30 fpm above 30 feet. Bonus In case you missed it the first time, this baby will dance with three partners at once: three wireless transmitters on three separate breathing mixes that can be accessed at any time during the dive. Also, the three nitrox mixes are all programmable from 21 to 99 percent oxygen. MSRP $1,000 Contact www.oceanic worldwide.com