This is the Valve Spring Retainer for the O.S. Max FS70S II Engine. The retainer is located on top of the Valve Spring FEATURES: Black steel construction INCLUDES: One Spring Retainer REQUIRES: Assembly into the engine SPECS: Outer Diameter: 7.7mm (.305") Inner Diameter: 4.6mm (.182") Thickness: 2.6mm (.103") COMMENTS: Two retainers are required in the FS70S II cmc 4/11/01 ir/jl