Alarm Distance: When the mainframe and the magnetic stripe are closed, and the distance is within 1cm, there will be no alarm. When the mainframe is separated from the magnetic stripe and the distance is 1cm away, an alarm will sound. "Attention-Grabbing Thieves: Extremely loud 105 dB alarm helps wake/alert homeowner or renter, helps deter intruder and possibly notifies neighbors." Intimidate Thieves Away With Extremely Loud: If a burglar opens the protected front/sliding door or window, a magnetic switch inside the sensor, will trip, which sets off the security system. Super loud alarm of 105dB, scare thief away. Very Easy Installation: No wiring needed, plus sensor mounts on either side of alarm for easier set up, 12 x LR 44 button cell batteries.(3pcs for each alarm device). Extensive Application And Easy To Use: Perfect for home, office, glass door, pet door, dog door, cat door, patio door, closet door, cabinet door, interior door, entry door, bedroom door, dorm room and even car door You can change the batteries easily when the batteries exhaust. Besides, superior adhesive backing for optimum sticking power. All-round 24H Sale Service: The professional material insure the quality of item. Please contact our Happy Shopping Customer Service or send email to our company's mailbox, we will give you a satisfied solution in 24 hours. Item Name: Door/Window Alarm System; Main Material: ABS+Electronic Parts; Main Color: White; Size One(Mainframe System): 5.5 x 3.7 x 2cm / 2.17" x 1.46" x 0.79"(L * W * H); Batteries: 3 x LR 44 Button Cell Batteries Each Device(Include); Size Two(Magnetic Stripe): 5.2 x 1.5 x 1.5cm / 2.05" x 0.59" x 0.59"(L * W * H); Total Weight: 190g / 6.70oz; Package Include: 4 x Door/Window Alarm System.Products from Bazhou's store