Drop-in excellent quality replacement for OE pistons and rings that comes in a complete kit of a pair of pistons, rings and pins. I purchased these as replacements for the originals when replacing cylinder studs in a 900SS motor. The higher compression requires more of the starter motor, but it does the job as long as the battery is in good condition. The JE kit is a much better value than OE Ducati pistons and rings and there is a power increase due to the higher comp ratio.