Sealed, 4 in round stop, turn, and tail light may be used on both curbside and roadside of vehicle or trailer. Fully automated manufacturing process ensures consistent quality and reliability. Features extra wide, spin-welded, tongue-and-groove lens lip andwaterproof seal. High performance, copper alloy conductors eliminate the possibility of wire failure. State-of-the art bulb design features three supports for the minor filament and two supports for the major filament providing long bulb life. Wedge-basesocket prevents premature bulb failure. Includes light, grommet and 431-491 straight plug. 4-1/4 in Diameter.