Model range 118®, 128, 138 ProFix® 2 With its diminutive dimensions of 66 mm x 20.1 mm x 25.5 mm, effeff's Electric Strike 118 is the smallest ProFix® 2 electric strike in the world. Fail-locked 118® ProFix® 2The door can only be opened while contact is made. When operated with an alternating current, a buzzing sound can be heard. There is no buzzing sound with direct current operation. Hold-open function 128 ProFix®2The latch bolt controlled locking pin in the centre of the electric strike latch keeps the electric strike unlocked until the door is opened, even after contact has been made. Fail-unlocked 138 ProFix® 2The electric strike is locked for as long as the power is on. If the power is switched off or if there is a power cut, the electric strike latch can be moved and the door can be opened.