Aeris CompuMask HUD (Heads Up Display) Hoseless Nitrox Dive Computer with Tra... Hoseless air integrated technology - In-Mask Digital Optic System - Hoseless Air Integrated Technology Patented Air Time Remaining Algorithm - Air, Nitrox, Gauge and Free Dive Modes Audible and Visual Alarms with User Alarm Acknowledgment - Backlighting may be adjusted underwater for brightness as well as full-time or on demand use Includes ACI PC Download and Settings Upload Software and USB cable Diver-Replaceable Batteries - Safety stop count-down timer