Alarm siren come with come with 1 PIR Sensor, 2 Remote Controller.All things had been coded, you just install it and it will work well SPECIAL:Solar Cell ,Green Life. Doesn't need to much sun, it can be with rain and dark days for 10 days or more and still charge without any problem LOUD: 120db alerts, with strobe-lights flash. Unique tamper alarm function design. If someone trigger it, it’s certainly loud enough to discourage an intruder. A good deterrent to be used in conjunction with other mechanisms/deterrents USEFUL: The remote control key fob to arm or disarm. Under arm status, it will alarm when somebody trigger the PIR motion detector,burglar siren will scare off the intruders away from home/garage /courtyard wherever we use POWERFUL : It can work as a wireless siren,or as an alarm panel by working together with other sensors Max.99pcs, Weight: 2.54 pounds, Manufacturer: ChiTongDa