The F1000-550 Discovery Ionization Smoke Detector has a molded self-extinguishing white polycarbonate case with wind-resistant smoke inlets. Stainless steel wiper contacts connect the detector to the terminals in the mounting base. Inside the detector, the case is a printed circuit board that has the ionization chamber system mounted on one side and the address capture, signal processing, and communications electronics on the other. The ionization chamber system comprises an inner reference chamber inside an outer sensing chamber. The outer sensing chamber has smoke inlet apertures which are fitted with an insect-resistant mesh.