This kit comprises of the Narked at 90 heads up display. The fantastic 3 cell simultaneous monitoring from the shearwater electronics encased in the slim line Narked housing. It is fitted with isolation electronics and 3 MOLEX connectors. A HUD holder is provided that fits approximately 50mm diameter loop fittings and 3 Gold cell splitters for easy connection to cells.
This Monitors three sensors and displays the PPO2 on three LEDs. Each of the connections corresponds to an LED on the display. Each LED is a dual colour LED. It can show red, green, or orange (both red and green on.)
There is a button on the box and it controls the HUD. One push turns it on and one push turns it off. Three pushes calibrates. If, when you turn it on, you get orange flashing for 30 seconds, that indicates a low battery.
To calibrate, you need to push the button three times within 1 second. It might take a little practice to get this, but it is intended to prevent accidental calibrations. If you successfully do the calibrate sequence, all three lights will come on bright red for 5 seconds. If you don't see that, it didn't get the calibration command.
After you calibrate, each of the sensors should be flashing one orange. That means the ppo2 is between 0.95 and 1.05. The actual value is uses for calibration is .98. If a sensor fails calibration, it will flash one red and one green.
The rest of the flash pattern is:
The number of greens is the number of tenths above 1.0 so three green is 1.3 ppo2.
The number of reds is the number of tenths below 1.0 so two red is 0.8
The box contains the processor and battery. To change the battery, unscrew the battery cap. The battery should last for months or even years. The battery is a 3.6 V Lithium -SAFT LS14250-BA
The HUD box straps or bolts onto the breathing hose up beside your head or the rebreather case so it is completely out of the way.