Connect drawers, jewelry boxes, or any other valuable containers to your hardwired alarm system. The Normally Closed Tamper Switch can be used with any security system with normally open circuits, and its small size makes it easy to hide and install. Security wiring is sold separately to connect the tamper switch to your alarm system. A silver-plated contact ensures reliability and long-term operation. This tamper switch is for use with alarm systems with normally open circuits. For alarm systems with normally closed circuits, use the Normally Open Tamper Switch.