Series 15 Ball Bearing Utility Block - Exit Block. Features: Smallest and lightest ball bearing block available. Precision molded acetal sheave running on stainless steel ball bearings provide high performance & low friction. Single loop head blocks include an O-ring to separate running line from head lashing or fixing. Features a flush rivet to minimize cutout and facilitate installation. Featuring a formed single piece housing for maximum strength and minimal rope wear. Applications: Dinghy control lines, vangs, cunninghams and tweakers, shock cord tensioning systems. Materials: BB sheaves: UV stabilized acetal. Ball bearings: Stainless steel. Cheeks: Grade 316 stainless steel. Additional product info: Great Product. Item Weight: 0.05 Pounds. Item Dimensions LxWxH: 4 x 2 x 1 inches. Package Weight: 0.05 Pounds. Package Dimensions: 4 x 2 x 1 inches.