Step Key Stock,0.438 in Base H,0.875in W, Base Height 0.438 in, Material Steel, Material Grade/Class Grade 1018, Finish Zinc Plated, Length 12 in, Length Tolerance +0.000/-0.125 in, Overall Width 0.875 in, Overall Width Tolerance +0.000/-0.003 in, Step Height 0.375 in, Step Height Tolerance +/-0.005 in, Step Width 0.75 in, Step Width Tolerance +0.000/-0.003 in, Straightness Tolerance Not Applicable, Standards RoHS Compliant, Pack Size Small Pack, System of Measurement Inch, Key Shape Step Zinc-plated 1018 grade carbon steel key stock works on couplings, sheaves, sprockets, and pulleys. Use it when mating mismatched keyways, gears, and shafts.