Fail secure(NO) means when power off, the lock is locked; Fail safe(NC) means when power on, the lock is locked Advantage: Low Temperature, safe & Durable Low Power, Environmental Protection Special photo-electric control, three steps current application Long Life with 500000 cycles MOV Provides Reverse Current Protection Superior Strength Aluminum Alloy, Solid Stainless Steel Bolt Fail secure - locked when power is off. Suitable For Wooden Door, Glass Door, Metal Door, PVC Door Specifications: Lock bolt: The diameter og 12.5mm stainless core,extending the length of 15mm Main body: 200(L)x28(W)x3(H) mm Net weight: 740g Voltage: DC12V Current: 0.14A (Standby) / 1.3A (Start) Solid Bolt : Polishing housing, 1000Kg Holding Force Diagram Red wire for + power Black wire for - power White wire for COM Yellow for NC ​Blue for NO Package include: 1 x Electric Lock 1 x Extension piece 1 x Face-plate 1 x Magnetic Base 1 x Bracket 1 x Screw Kit 1 x Manual