DT309M with Min. Volume at current marketing. 1. Dual infrared and X brand microwave. 2. Hi-technology microprocessor. 3. Active temperature compensation curcuit. 4. Anti-disturbance from pets. Below 25Kg 5. Highly sensitive parabola curtain lens optical system can greatly increase the detector's capture singal ability in sight and obtain general sensitivity within the detecting range 6. Quick installation