This is a front bearing from Boca Bearings designed to fit the O.S. MAX .21 RG, VZ-B and VZ-B V-Spec, RB Concepts WS7, WS7II, Novarossi P5, P5X, 421B, Pllus 21-5 and 528XR off-road competition engines. This bearing will also fit any other .21 to .28...