The Homelus Window/Door Alarm is a sleekly designed unit enabling it to function with sliding glass windows and doors. The Window/Door Alarm is triggered by both window vibration and entry opening. Place the included magnet on the outside frame of any window or door you wish to protect. When opened by an intruder, the magnetic circuit is broken and a loud alarm will sound. The alarm unit will also sound when window vibration is detected. Printed on the reverse side of this product is a red warning label that can be seen outside through the window. It notes that your property is protected by Homelus and deters potential burglars. Its ultra-thin profile makes if perfect for sliding glass doors. FEATURES: Dual trigger magnetic/vibration Alarm Simple "peel and stick" installation Warning sticker to defer theft Loud 100 dB alarm SPECIFICATIONS Color : Sliver & Gray Batteries: 3 x LR44/AG13 button cell batteries (Included).