This is the Rear Bearing for the OS Max 160FX Engine. FEATURES: Solid steel construction. Open race on both sides for full lubrication. INCLUDES: One Rear Ball Bearing REQUIRES: Assembly into the engine. SPECS: Inner Diameter: 0.79" (20mm) Outer Diameter: 1.6" (41.9mm) Thickness: 0.47" (12mm) sml 9/23/00 ir/jl updt jxs 1/14/04