1. 4 in 1 Multi-Function - - General Alarm, Constant Alarm, Closing-door Alert (Time Delay), Doorbell 2. Batteried by 2pcs AAA batteries ( not included ). 3. Self-Adhesive, easy to install and operate. 4. 108 dB Loud Alarm can effectively prevent intruder entering through your door or window. 4 in 1 Multi-Function: 1.General alarm mode It alarms when doors or windows are open Stops when they are closed. 2. Constant Alarm Mode It alarms at least when triggered. 3. Time Delay Mode It sounds "di-di-di" when doors or windows opened 15 seconds later (Can set the delay time 3 or 15 or 30 or 60 seconds, the factory default is 15s). This is perfect for freezers or refrigerators. Material: ABS colour: White Package Contents: 1 x Door or window Alarm 1 x Magnetic Stripe Double Sided Sticker User Manual Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is 1-3cm. Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement. Sold by-YJL official store