• Reliable 433 MHz technology • WS4904P model version provides pet immunity up to 60 lbs (27 kg) • Digital signal analysis for consistent detection throughout the coverage pattern • Exceptional catch performance at elevated temperatures • Patented Multi-Level Signal Processing (MLSP) for accurate detection of human IR energy over a broad range of temperatures • High-traffic shutdown • Temperature compensation • 1 long-life lithium battery included; capable of up to 9 years of battery life • Sensitivity adjustment to configure the detector for “normal” (high sensitivity) or “hostile” (low sensitivity) environments