The SR 623 uses six, two pole hermetically sealed, gas filled relays to provide a total of twelve poles of switching. Relays are qualified to MIL-R-39016/6.

* Certification: FAA PMA
* Max Pick up Voltage: 18VDC
* Min Drop Voltage: 1.5VDC
* Max Contact Rating: 2A @ 28VDC Resistive Load
    .75A @ 28VDC Inductive Load (200mH)
    .16A @ 28VDC Lamp Load