Firewolf Advanced Photoelectric Smoke Detector, 2-Wire (FW-2) Detects all types of fire including: paper, wood, gasoline, polystyrene, smoldering fires, etc. Dual LEDs for 360 degree visability (with flashing cleansing indicator) Superior chamber and photoelectric beam design enables precision detection of even minute particles Superior insect screening Compatible with 12V/24V power supplies