This stop light switch fits Mack air brake systems and is built as a replacement for the original electrical switch. Mounted in the brake circuit, it closes the connection when the pedal or treadle valve is actuated, triggering the brake lights to warn trailing traffic. It is sold individually for technicians servicing Mack air brake electrical components.Interchanges:Mack 745-286392Mack 745-287416LST-3713FeaturesSell pack: 1 EachCategory: Air Brake PartsTech SpecsSell Pack: 1 Each