Sleeve: This Piston/Sleeve set is optimized for use in EFRA/IFMAR competition events and is made from hard chromed brass. This is a NOVAROSSI WORLD S.r.l. Product: 13612 Backplate: we have made this backplate with a special steel inlay, this reduces friction and wear when the conrod touches it. The round shape reduces the dead space inside the engine. This is a NOVAROSSI WORLD S.r.l. Product: 16604 Rear ball bearing: This engine has steel precision balls in the rear ball bearing. This is a NOVAROSSI WORLD S.r.l. Product: 28609/1 Combustion chamber: The combustion chamber is supported by an O-Ring which is placed between the combustion chamber and the crankcase to reduce the vibrations of the combustion chamber. This is a NOVAROSSI WORLD S.r.l. Product: 85607 Crankshaft: The crankshaft is made from high quality steel and is available in "TURBO SG" version. It has a diameter of 11.90mm. The increased diameter provides more torsional stiffness. This is a NOVAROSSI WORLD S.r.l. Product: C5TGF