Series 20 Ball Bearing Block - Upright LeadFeatures:Lead blocks are a low profile solution for leading halyards or other rig sail controls back to cleats or jammersPrecision molded Acetal sheaves running on stainless steel or Torlon(R) ball bearings provide high performance & low frictionApplications:Typically used for halyards at the mast baseMaterials:U.V. Stabilized Acetal sheavesStainless steel ball bearings & Load housingSpecifications:Sheave : 20mm(3/4)Max. Rope : 6mm(1/4)Fastener : 4mm(5/32)M.W.L.: 250kg(550lbs)B. L.: 550kg(1,210lbs)Weight: 18g(0.6oz)