Tork Door Trip Switch APPLICATIONS: For unlocking or locking metal or wooden doors using low voltage wiring. For AC, use TA591 or TA592 transformer. FEATURES: Signals automatically as door is opened. Commonly used on store doors to announce entrance of customers. Mounts on top of door frame. Solid cast brass. Size 3 X 1 5/8" VOLTS: 12-24VAC AMPS: 2