Skylink PS-434W Wireless Indoor Outdoor Burglar Alarm Alert Security Infrared  Motion Detector Sensor | Affordable, Easy to Install DIY Accessory for SC Series Systems NO MONTHLY FEES and easy DIY (Do It Yourself) installation with ball joint mounting kit COMPATIBILE with SC-10W, SC-100W, SC-1000W systems. DETECTS AND ALERTS when motion is detected around your home or business. WATER RESISTENT for indoor or outdoor use SENSE MOVEMENT UP TO 40 FEET AWAY with 110 degree arc.