Kleinn Air Horns Hand Pull Lanyard Valve is expertly engineered for Roof-Mounted Horns. Kleinn Air Horns created this Hand Pull Lanyard Valve to facilitate the engagement of Sounding the Roof Mounted Horn just as a trucker would. This Kleinn Air Horns Hand Pull Lanyard Valve features an O.D. Tube Compression Fitting Inlet and Outlet measuring 1/4-Inches.