McKissick Construction Block, Series: 680, 5/8 in, 3/4 in, 7/8 in, 1 in Maximum Cable, 45 ton, 18 in Sheave Outside Dia, Bronze Bushing Bearing, Roll Forged Sheave, 4 Grooves, 42.88 in L x 18.12 in W x 13.33 in THK