LiftMaster 835LM Chamberlain CWA2000 Vehicle Pedestrian Perimeter Alert Motion Sensor Detects motion up to 30 feet away with wide 120 degree coverage Transmits signal to base up to 1/2 mile away Motion Sensor features adjustable sensitivity control to prevent false alerts from small animals Detection indicators with light and sound Receiver features a 1-hour mute feature (patent pending) Connect 1 base station with up to 4 motion sensors