I bought 3 of these at the same time. All three are smart well built easy to install. They are also easy to adjust To fit beam with, and can be used on H beam (that are flat) and I beam (that are slightly angled). BUT the ball bearings are rough to very rough rolling…ie as if one has over tightened the bearing in place and the pressure creates a rough (NOT smooth) travel along beam. Worth buying for the low price if high production use is not intended.