Instant Alarm (4 Pack) is the wireless alarm system kit that increases your level of security to virtually any door or window.Simple to apply, just peel of the adhesive backing, stick it in place and turn on. Perfect for people who live alone or elderly loved ones who want more piece of mind. Great protection for doors, hotel rooms, houses, dorm rooms, apartments, offices, medicine cabinets, windows, drawers, pool gates and sliding doors. Worried about intruders breaking in? Not any more with this 4 pack security system kit. Each measures 2.75 H x 2 W x .5 W Batteries Included and Ready to Use!