Abstract: An alarm switch is mounted by means of a support for actuation by relative movement between the support and a member such as a door or window. Switches are carried by the support and an operating arm for the switches extends from the support and is adapted to be pulled a limited distance relative to the support for actuating the switches to complete an alarm circuit. Interengageable gripping members on the arm and the member pull the arm the limited distance relative to the support to actuate the switches when there is relative movement between the member and the support, and automatically disengage to free the member from the arm when the relative movement is greater than the limited distance. The gripping members are selectively disengageable to permit relative movement between the support and the member without actuating the alarm switch.