[3 sensitivity grade] There is an adjustable sensitivity switch on the side to control the high-medium-low sensitivity level of the door alarm [Loud alarm] 120-decibel high-pitched alarm remind the owner and scare off intruders [Non-slip bottom] non-slip rubber pad is used on the bottom to prevent thieves from entering without an alarm [Easy to install] no wiring required; battery-powered (1x9V battery required, not included); just put it under any door [Function] You can use it as a common door stopper when turn down the ON/OFF switch, hold the the open position. Volume: equal 120(dB) Working voltage:9(V) Working current:0.2(mA) Three sensitivity:High, Medium, Low Shape:Wedge-shaped [Applicable scene] perfect for bedrooms, hotels, apartments, dorm rooms, front doors, etc; peace of mind when traveling or working alone Power Suplly:1 x 9V battery(Not included batteries) Colour:As Shown Material:Stainless steel+Plastic Size:14x4.5x4cm Package Contents: 2 x Door Stopper Security Alarm Only the above package content, other products are not included. Note: Light reflection 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.