This is a replacement ProTek R/C 14x25.4x6mm Ceramic Rear Bearing, intended for use with the ProTek R/C Samurai 321B, RM.1, RM, S03 and R03 Nitro Engine. This bearing can also be used with the O.S. VZ-B V-Spec, 30VG, the original Novarossi P5, 421B and...