When a "fail-safe" electric door lock looses power its default position is to unlock the door. Typically the door stays in whatever position it is in (open or shut) during the power loss unless it is designed to swing open when unlocked (using a spring or counter-weight, etc.).

• Fail-safe door strike - unlocks door during power outage
• Power: 12VDC, 400mA
• Dimensions: 128mm x 32mm x 38mm (5.04" x 1.26" x 1.50")