Includes: R6C-2RU TH9/C3 (1 pc) & MR6902C-2RU TH9/C3 (1 pc) Ceramic High Performance RC Engine Bearing Kits. Our Ceramic High Performance line of RC Engine bearings have a special heavy duty seal that is designed to cut down on leakage through the front of the engine. These bearings have ceramic balls, a high speed retainer and a C3 fit.