Martin BK27 1 1/8 FHP Sheave BS, 4L/5L or B Belt Section, 1 Groove, 1-1/8" Bore, Class 30 Gray Cast Iron, 2.7" OD, 9189 max rpm, 2.1 Datum/2.5 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 4L/5L or B belt or cross section One groove for single belt use