Dependable TechnologyMotion detection: A complete stand-alone motion sensor based alarm system, the PIR motion detector features a 120 detection and 180 flip design, communication range of up to 328ft/100m (Sound range in open place) and detection range of the infrared sensor of approximately 16-26ft/5-8m, 125db alarm or loud chime mode and state-of-the-art passive-infrared (PIR) to detect any movement within the detection zone to keep you informed and safeEasy InstallationJust install it in the right place: mounted on the wall or mounted vertically on the ceiling. It is simple to install the motion alarm with 3M tape and 360rotatable wall mount. No monthly fee, no contract, No wifi network is needed.Hassle-free SetupPowered by 3 AAA batteries (Not Included) or USB cable. Wire-free design due to battery powered does reduce hassles when installing the motion sensor. 360 rotatable bracket features wider detecting angle, which is ideal for multi scenes like home, office, warehouse, etc. (Notice: Do NOT install it outside since the sensor is NOT waterproof.)Arm/Disarm in a SecondSimply slide one button on Remote Control to arm or disarm the sensor when you need.EXPANDABLE Expand this A1 PIR motion sensor with further FeelGlad Home Alarm System accessories. you can expand this system with up to 50 additional sensors or 20 multiple receivers.