This is a Protek R/C Ceramic 14x25.8x6mm "MX-Speed" Rear Engine Bearing, and is intended for use with any nitro engine that requires a 14x25.8x6mm rear bearing. ProTek MX-Speed engine bearings offer decreased resistance, increased speed, load handling capabilities and extended bearing life. The bearing dimensions are 14mm inner, 25.8mm outer and 6mm thick. This bearing is open to allow oil to lubricate the bearings during use. This bearing will also fit any other .21 to .28 competition engine that uses the same bearing dimensions.
They also have 2 distinct advantages when compared to other bearings.
Why Ceramic? Our ProTek Ceramic Engine Bearings are a hybrid type, featuring Stainless Steel outer races with Si3N4 silicone nitride ceramic balls riding on a polymide inner race. Ceramic bearings have many advantages over standard steel bearings, such as decreased weight, higher RPM capabilities, increased corrosion and wear resistance, as well as reduced friction and vibration.
Advantages of Ceramic: