Optical and thermal smoke via radio detector, frequency 433Mhz (63bit). Selectable detection technology, smoke and heat, or smoke or heat. Siren included 85dBA at 3 meters, test button with led, 8 selectable sound tones. Heat sensitivity from 58º to 72º C. 2 batteries. Certificate with respect to EN14604: 2005 / AC: 2008 and BS5446-2: 2003. Dimensions: 109x62mm.