The Kleinn Model 310 is a premium hand-pull chain lanyard valve featuring a rugged nylon and metal construction designed for roof-mount air horns to let you blast your horn with the authentic feel and control of a real commercial truck driver. Engineered for direct mechanical activation, this high-flow valve connects seamlessly to your roof-mounted horn setup, delivering an instantaneous blast of high-pressure air the moment the chain is pulled. Built to withstand continuous use and harsh cabin environments, the complete assembly comes equipped with a durable pull chain and a heavy-duty mounting bracket, making it the perfect vintage-style upgrade for semi-trucks, custom rigs, and big-rig vehicle installations.