The XRS is a steel color chain. The X-ring is a very thin o-ring with an X shape which offers a drag reduction on rollers and side plates. The reduction in drag is such that efficiency is almost increased to the same level as a regular roller chain, with the longevity of a regular o-ring and fit to handle at least 200 horsepower. This is the quality Tsubaki chain which combines superior strength and performance with the longevity well known to o-ring type chains. Average tensile strength 45.1 kN. Note: These chains come with a pin link (rivet style) master link. A clip style connecting link (506125 XRS plain) must be ordered separately if desired.