The alarm is installed on the door or window. If the thief wants to open the door or window, the alarm will immediately send out alarm sound. Alarm application magnetic sense control technology, long service life, simple installation. Use adhesive paste, no need for screw installation, the direct paste can be used! Does not damage household items. More than 120 decibels of alarm sound, safety protection of your home. Sensitive alert sensor, 1 cm of movement can trigger the alarm. Use 3M double-sided adhesive tape for easy installation. Safe and convenient, easy to operate. Five core competency guarantees Easy to install can be installed at any open and close parts Super sensitive induction, more than 1cm error can trigger an alarm Quality assurance, you can protect your home at any time Specifications: Power: 3*Button batteries. Type: 4/8/16 Pcs. Size: 6.2x 4 cm. Color: White. Weight: 38g.