The Daystar Stingers fit in a conventional 2-inch weld-on bumpstop can. They have four inches of travel and use three EVS foam cushions to slow down (and eventually stop) the compression of the bumpstop shaft. Each Stinger bumpstop comes with three blue EVS foam cushions and three black ones. The blue ones are softer and the black ones are harder. You can mix and match to get your desired bump effect. The Stingers have an optional weld-on cap that allows you to place the bumpstop anywhere you can weld the cap to. Daystar also offers a short version of the Stinger for tight spaces. The short versions offer 1.5 inches of travel and can also utilize the weld-on top cap for mounting.