The Oregon 22209 Power Mate rim sprocket system features a 3/8" pitch, 7-spline (SD7) rim designed to deliver smooth, efficient power transfer on a wide range of chainsaws. Its two-piece design with a replaceable rim helps maximize bar and chain alignment, reducing wear while lowering long-term maintenance costs. For optimal performance and protection of your cutting system, the complete assembly should be replaced after every three rim replacements.