Adjust engine valve clearance using commonly available 9.48mm shims rather than costly Polaris shim buckets. For use with Polaris 570,900, 1000 and Turbo Prostar engines (see application chart for specific fitments). Specifically designed alongside Hot Cams camshafts for these same engines, and designed to work with OEM valves, springs, camshafts and aftermarket high performance camshafts.