Ideal Security SK602G QH Wireless Motion Package Battery-Operated & Weatherproof-1 Sensor and 1 Alarm, Grey Set includes 1 pir motion sensor unit and 1 receiver/alarm unit Add additional sensors: up to 50 sensors can be linked to the receiver (skqh652qkp3) 4 alert settings: loud alarm, loud chime, soft chime, lights only, charcoal grey body, blue LED motion indicator Communication range of up to 390 feet between motion sensor and alarm unit. Senses motion over a 45 degree arc, up to 26 feet away, motion sensor unit can be used outdoors Low battery indicator. Batteries are not included, optional power supply for the alarm unit (skqh652chg)