Small Alarm: Compact design, smaller than most door window alarms. DIY installation, just peel and stick. It is easy to mount this alarm on any type of doors and windows, swing doors, rolling doors, sliding doors, etc. Loud Anti-theft Alarm: In continuous alarm mode, once triggered, the continuous alarm will be a great deterrent for thieves and intruders. In doorbell mode, a loud sound will be an effective and quick warning when your kids or pets sneak out of the house. 4 Working Modes: general alarm, continuous alarm, door closing alarm, doorbell mode. Simply slide the side switch up and down to adjust the modes, each mode corresponds to a different sound. Please refer to the product picture for details. Ideal for: Not only suitable for all kinds of doors and windows, but also for drawers, filing cabinets, safes, garage, RV, office, warehouse, shop, etc. Low battery indicator: Powered by 3 LR44 batteries. Low battery consumption and long standby time. It will sound "Du Du" every half