Superior 1 Ton chain fall on trolley. The rollers measure 3-3'4" in diameter. There are four sets of seven spacers that make the trolley assembly adjustable to accommodate I-beam dimensions of 3-1/4" to 4-3/4" wide. The pictures show the rollers set at both the widest and narrowest positions. The chain drop is 8 feet. This is a heavy, older, well made piece of equipment. It's located in Oakham, MA, thirty minutes west of Worcester, MA.