Bosch Wireless RF835E Tri Tech Sensor is a simple to install Sensor that incorporates 3 Sensor Technologies to make it more stable in harsh environments. This sensor can be easily added to any Bosch Wireless Security Systems (Sold here). These sensors are an ideal solution for installation in rooms or warehouses where drafts from air vents, air conditioners and roller shutters are prominent. This sensor can also be used as a Pet Immune Sensor that will NOT detect animals up to a combined weight of 30KG. Certain Conditions apply so call or write to us to help determine if this sensor will meet with your requirements. The RF835E has a room coverage of 11 meters x 11 meters and will not look through walls, doors and windows. The RF835E sensor combines Passive Infra Red (PIR) and a Microwave Sensor. The outputs of these sensors are analysed by a processor to determine if the movement is an alarm condition of false alarm.