Steinel quality is 240 duo motion detector up to date sensor technology which when mounted on outside corners makes surveillance of two house walls possible a second sensor is therefore not needed two highly sensitive detectors arranged next to each other at a special angle allow reliable surveillance of large areas up to 230 minfrared wall sensor ideal for surveillance of large house fronts as well as corners outsidethe detection area 2 m x 12 m temperature stabilised 230 m is limit