For over 150HP applications. Gold colored chain. Comes with hollow rivet link for easy installation with industry standard tools. The X-ring is a very thin ''O-ring'' with an X shape which offers a drag reduction on rollers and side plates. 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. 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.- Gold colored link plates - Low friction ''X-ring'' seal ring- For over 150 HP bikes. Note: These chains come with a pin link (rivet style) master link. A clip style connecting link (506143 RQ1) must be ordered separately if desired.