Wireless Photoelectric Smoke Detector.  Automatic drift compensation.  Built-in, dual-senor heat detector.  Built-in 85dB horn.  Local test button.  Low-profile design.  High/Low sensitivity reporting.  Low-battery indication.  Easy-maintenance removable smoke chamber.  Non-contact sensitivity testing with FSD-100handheld test meter.  Long-life lithium batteries included.  UL/ULC/EN listed for commercial and residential applications.  Compatible with all DSC 433MHz wireless receivers.