For efficient and strong cargo handling, look into US Cargo Control's 4" Double L Track Sliding Winches to create multiple tie-down points on your flatbed trailer. Use this sliding winch when you have sliding double L winch tracks (or LL tracks). The sliding mechanism allows you to slide the winch along the track to easily created desired tie-down points on your flatbed. Slide in either direction on the winch track to line up and secure your cargo with winch straps. The truck tie down winch locks in place when tension is applied. The trailer strap winch holds up to 20' of 4" webbing. Each sliding winch for flatbed trailers is made of durable steel with a black-painted finish, protecting itself from the elements. With a working load limit of 5,500 lbs., you can trust our trailer sliding winches to withstand heavy loads and ensure the toughest load conditions. For tensioning, the WSTDA recommends in section 4.3.5 that " When using any winch, the winch mandrel shall have a minimum of two (2) and a maximum of four (4) wraps of webbing. Two to four wraps will appear like four to eight layers of webbing. Less than two wraps may result in strap slippage; more than four will place unnecessary strain on the winch. Excessive straps of webbing on the mandrel may reduce the working load limit (WLL) of the winch and may interfere with proper operation." If you're looking into creating an ideal flatbed hauling tie down system, US Cargo Control's 4" Double L Track Winches are perfect flatbed tie downs to use for smooth cargo securement.