200-30 Ball bearing cheek block. Curved base fits up to 2" diameter spars. Delrin(tm) ball bearing sheave ensures low friction. Stainless steel cheek and base provide high safe working load. Sheave Dia. 1-1/16" (27 mm), Max Line 5/16" (8 mm), L 3-1/2" (89 mm), W 1" (25 mm), H 21/32" (17 mm), Fasteners (4) #10 RH (5 mm), C/C 3" (76 mm), SWL 900 lbs. (410 kg), Weight Stain. 1.5 oz. (42 g)