The alpha-series motion alert kit contains a pir (passive infrared) motion sensor & a chime receiver unit. It’s very easy to install as all units are battery-powered and completely wireless. Use the included installation accessories to set up in minutes. Mount the pir motion sensor wherever you need to know about movements and be alerted audibly and/or visually from the chime receiver unit that has 3 selectable volume levels. This kit is perfect for creating cost-effective safety in and around your home with modern units that have reliability, accuracy and ease of use at their core. Features the chime receiver unit has adjustable volume, silent mode, & can be paired with up to 60 sensors & doorbells connect in minutes with easy mounting, pairing & convenient wire-free operation uses 3 x aa batteries for chime receiver & 3 x aaa batteries for sensor - not included no hub, internet, or phone connection required long wireless range up to 100ft/30m from each sensor to receiver the pir alert sensor detects motion up to 13ft/4m away with a weatherproof design for monitoring driveways & other outdoor locations ndaa compliant