To protect costly sensor units of beam type smoke detectors from damage leading to misalignment and false alarms. This model protects the vital sensor units of projected beam type smoke detectors in large areas. These areas include gymnasiums, warehouses and auditoriums. STI Smoke Beam Guards are designed to protect both transmitter and receiver sensors. STI-9623 is used on Detection Systems 240 and DS 241 long-range projected beam smoke detectors. Installation is simple with anchors and screws provided. Backed by a lifetime guarantee. As all STI protective covers, Smoke Beam Guards are backed by a lifetime guarantee against breakage in normal use. They are constructed of 9-gauge, welded steel wire coated with a tough, corrosion resistant polyester shell.