The IQ-900 can be operated as a watch, Air computer, Nitrox (EANx) computer, digital depth gauge/timer or as a free dive depth gauge/timer. The Zen's large alphanumeric and backlit display allows for high legibility in or out of the water, although its size is that of a normal style watch. In addition to offering the latest comprehensive computer features, the Zen adds a Deep Stop function for enhanced safety.

Deep Stop Function
The Zen computer features an optional deep stop function for additional safety. The deep stop mode is activated when a dive exceeds 80 FT (24M) for more than 1 second. Upon ascent past 50 FT (15M), the computer will display a Deep Safety Stop screen and the recommended stop at 40 FT (12M) for a period of 2 minutes. This deep stop is highly recommended as additional opportunity to off-gas, but is not mandatory. If the diver chooses not to serve the stop it will not adversely affect the remaining No-Decompression Limits of the dive.