This is a aftermarket  top overhaul kit featuring 2 new pistons, moly coated for low friction w/dual rings, pins, circlips , full major overhaul gasket w/ crank seals  kit as shown. This set exceeds the MFGs specs , Designed to replace the oem elkos in all respects.

Smoother running due to better balance, stonger and better heat transfer. These are hard anodized crowned (keeps the heat up top) and feature moly coated skirts to reduce friction and heat.

We run em in our trikes and use them in our shop for the past 10+ years

This is set is for 72 mm std bore  503  rotax.