Martin AK46 P/B Plain Bore FHP Sheave, 3L/4L Belt Section, 1 Groove, 1/2" Bore, Class 30 Gray Cast Iron, 4.45" OD, 5575 max rpm, 3.86" Pitch Diameter/4.2 Datum Classical V-belt sheave fits widely available, classical profile V-belts suitable for use in many existing drive designs Class 30 gray cast iron for resistance to wear and galling 3L/4L or A belt or cross section One groove for single belt use