Features: - Self-adhesive, easy to install and operate. - The 108 dB loud alarm prevents intruders from entering through your door/window. - Low battery warning, when the battery needs to be replaced, the LED will flash once per second. - 4 in 1 multi-function: general alarm, constant alarm 30s, door closing alarm (delay), doorbell, set the appropriate mode as needed. Specifications: Power by: 2*AAA batteries (not included) Package included: 1 x Burglar Security Sensor 1 x Magnetic Stripe Notes: 1. Manual measuring, please allow 1 ~ 3mm error,thank you. 2. Due to the difference between different monitors, the picture may not reflect the actual color of the item. We guarantee the style is the same as shown in the picture.