The Fathom Heads Up Display (HUD) utilizes a modified Smither’s code to display current ppO2 information. Designed as an add-on for CCRs that don’t come with a HUD, the electronics and battery are housed in a surprisingly small 1.5” diameter x 3” long cylindrical housing. On startup, the HUD indicates battery voltage through a series of flashes. The ½ AA SAFT battery lasts for years due to the low power consumption; however, divers can opt for a rechargeable battery that can be charged via a USB cable if they prefer. The LED display is reversible so can be worn on the right or left side while keeping proper left to right cell orientation and is light sensitive so automatically adjusts to ambient light conditions. The HUD is available with a Fischer connector, 4-pin AK connector, or an unterminated cable for hard-wiring into your CCR’s head.