3 Series Double Cheek Block with anodized Aluminum cheek. Delrin(tm) sheaves ensure smooth operation and high safe working load. Upper sheave safe working load 200 lbs (91kg), lower sheave 1000 lbs, (450 kg), Sheave Dia. 1-7/16" (37 mm), Max Line 7/16" (11 m), L 2-7/8" (73 mm), W 1-3/4" (44 mm), H 1-7/16" (37 mm), Fasteners (4) #10 RH (5 mm), C/C 2-3/8" (60 mm), Weight Alum. 4.2 oz. (119 g)