I've installed them on the side rails of trailers for guys inside of a pipe with cable attached to the end of the spring & then to the ramp so the spring is always in the pipe, safer that way. (you can buy them, I just copied it). Noel, if you're interested it's a good idea to run a clothesline cable or such through the center of the spring (when it's stretched out) & fasten it to your eye bolts. It'll stick out a little when retracted but if the spring snaps when you're raising or lowering it(that's when it'll break always lol), it stops it from flying & hitting you or your equipment.