.21 Rear Bearing 14 x 25.4 x 6.. This is a replacement special rear bearing for Novarossi brand engines that require the 14mm internal diameter with 25.4mm external diameter. The bearing dimensions are 14mm inner, 25.4mm outer and 6mm thick. This bearing is open to allow oil to lubricate the bearings during use. This will work with any Novarossi brand engine including the Top and Rex lines, for engines such as the P5, 421B and BS-21SB. This bearing will also fit the O.S. MAX VZ-B and VZ-B V-Spec off-road competition buggy engines, as well as RB Concepts engines that use a 25.4 rear bearing such as the C5. This bearing will also fit any other .21 competition buggy engine that uses the same bearing dimensions.