I just got the electronic version of Backscatter's Airlock Vacuum System. It screws into one of your housing's existing accessory bulkhead ports (my Aquatica AD800 has three accessory ports, and two strobe bulkheads). The Bulkhead is not included with the vacuum system and must be purchased separately. The system costs $424, and the bulkhead for my housing cost $75. The system is powered by a CR2032 3V coin battery. There is an external on/off switch. There are three LED indicators which flash green when the vacuum in the housing is greater than 6" Hg. Yellow below 6" Hg. Red below 3" Hg. When the unit is turned on with adequate vacuum present, it will flash green three times in rapid sequence. The three green flashes will repeat every three seconds for a duration of 30 seconds, and the will go into a "sleep" mode in which it only flashes green every 109 seconds. If while in sleep mode, the vacuum falls below 6" Hg, it will wake up and flash amber or red every 3 seconds for 30 seconds, then go back into a sleep mode that flashes every 109 seconds at the appropriate color for the current amount of vacuum. My unit shipped without instructions, so these time intervals and pressure specs were determined by my observation, and are not necessarily manufacturing specifications. The pump and valve system appear to be identical to Backscatter's non-electronic pump, which has been thoroughly discussed on this forum. I think the electronic version is worth considering because it gives you continuous feedback with respect to the vacuum in your housing. I am happy with the purchase, and the technician at Backscatter was helpful with my questions about the unit.
Edited by diverdoug1, 16 September 2013 - 02:09 PM.