Genuine Unistrut P2949 EG Trolley - 2 Wheel Unistrut Trolley Support, 437 Lb Max Load Genuine UNISTRUT Products from World's Longest Running Unistrut Distributor Stainless Steel Wheel Bearings Requires No Lubrication Design Load: 150-437 Pounds, Depending on Speed Works With All 1-5/8" Wide Unistrut Channel Series, Minimum 1-5/8" Height