For A belts, pulleys from 2 in to 12 in have keyways except 3/8 in and 1/2 in bores and 3/4 in bores in pulleys less than 4 in in diameter. All pulleys are with slotted headless set screws. In Sta-Pak cartons. For 4L or 1/2 in x 11/32 in belts.