With revolutionary advances, this short, more compact trolley is 50% lighter than competitive trolleys, yet every bit as tough! The 632 can negotiate radius curves as tight as 7" - 10". It features a unique double row, ball bearing wheel design for greater wear capacity. the bearings pre-packed with lifetime lubricant. Dust covers help to shield and protect the bearings for maximum service life. Larger V-bars are available for wider flange adjustment (inquire at time of order). Exclusive Dial-Fit collar quickly adapts trolley to wide range of beams and patented rails. Lifetime warranty.