Effective deterrent - quick and easy to install. Attach the small thief deterrent to your window, door, and all movable openings, such as a cat flap. If the alarm and magnet are separated by opening while the sensor is activated, a loud 95 dB alarm will sound. It's as loud as turning your stereo all the way up. Conveniently, each alarm unit in the set has a separate on/off switch. The long-lasting batteries provide a standby time of up to 2 years, allowing you to start your next vacation safely and worry-free. Door and window alarm in a 3-pack. Protects your property from thieves. Easy installation: with screws or adhesive strips. Suitable for doors and windows. With on/off switch. Battery-operated: LR44 button cells. Mini dimensions: each 6 x 3 x 2 cm. 3 alarm units including button cells for all devices.