The D285 and D285TH detector heads detect the large smoke particles which typically result from wood, paper, and fabric combustion. The D285TH smoke detector also has a +135°F (+57°C) fixed temperature heat sensor. Use in areas where the ambient temperature does not exceed +100°F (+38°C). These detectors are compatible with twowire or fourwire, 12 VDC or 24 VDC circuits. Also available are addressable bases for use on the POPEX bus.