DBI/SALA's trolley is re-designed and engineered for ease of use and superior performance. Non-corrosive double-shielded wheel bearings are maintenance free. Use in combination with self retracting lifelines. Glides effortlessly along the beam and provides horizontal mobility and fall protection. It is easy to install and operate, and combines light weight and high strength (5,000 lbs. Min. tensile strength). Fits 3" to 8" flange width thickness up to 11/16”. Meets or exceeds all applicable industry standards including OSHA, ANSI and the stringent ANSI Z359. Sold by the each.