Aluminum conductive foil to detect forced entry via glass doors, windows, skylights or even partitioned walls. The tape easily breaks, creating an open circuit which an alarm system can detect. The self-adhesive foil is 3/8in x 147ft (9mm x 45m). This product contains no lead. It has a paper backing when removed exposes the self adhesive backing. Use a foil squeegee to help your application go smooth. Use our foil holder to protect and prevent your roll of foil from damage and getting tangled.New applications and repairs should be top coated with our foil protector applied with a small foil brush. See How To Repair Alarm Foil and How to Install Alarm Foil