Harley Davidson Rocker Box Cover RSD Clarity Twin Cam Contrast Cut 0177-2034-BMHarley Davidson Rocker Box Cover RSD Clarity allow the viewing of internals of the engine. Harley Davidson Twin Cam Rocker box covers by RSD Fits all Twin Cam models 1999 up. All hardware is included to fit. Made in USA. This was probably the most difficult Clarity item to design. Engine Clearance was a major issue as we wanted to ensure it worked with most engine internals and highlift cams, while still fitting the tight clearance of the stock HD