While most motion detectors can be easily blocked, sprayed or obstructed - and therefore be rendered useless - Visonic's Anti-Masking detectors alert the user when they've been tampered with. The detectors include Visonic's DUET AM C/O and DUO 220AM and the TOWER- 10AM, 12AM and 20AM. They each assure users that their motion sensors are working properly and are not accidentally - or purposely - blocked.
