Series 20 Ball Bearing Block - Single. Features:. Low friction. High static and dynamic load capacity. Lightweight. Precision molded Acetal sheaves running on stainless steel or Torlon ball bearings provide high performance & low friction. Applications:. Dinghy control lines. Dinghy Vangs. Cunninghams. Traveller controls. Materials:. U.V. Stabilized Acetal sheaves. Stainless steel ball bearings. Grade 316 stainless steel load strap and head fitting. Impact and UV resistant, fiber reinforced Nylon cheeks. Specifications:. Sheave Ø: 20mm(3/4"). Max. Rope Ø: 6mm(1/4"). Pin Ø: 3mm(1/8"). M.W.L.: 250kg(550lbs). B. L.: 550kg(1,210lbs). Weight: 20g(0.7oz)