Made by a name-brand piston manufacturer, and are the perfect start for a road-going high-torque Mini engine. These are a hyper-eutectic cast piston, which means the silicon content is higher than usual, resulting in lower thermal expansion and more stable dimensions. Piston weight with pin and rings is approximately 400 grams. 9cc dish; special thin ring pack is included. Rings are not fitted to the piston when purchased, and it is recommended that they be sized to achieve the gap suggested by your engine builder. Sold in sets of 4.