Series 20 Single Becket Ball Bearing Orbit Block with Lashing is capable of loads up to 250kg (550lb) while weighing a mere 9 grams. It's so light that it needs to be lashed down! ( Block must be lashed through hub. M.W.L. & B.L. are dependent on the strength of lashing. Knots, splices, stitching will generally have a lower B.L. than the line itself.) Use for Control lines, kite bridles, leech lines, cascading vangs & cunninghams. Materials: Sheave: high compression strength carbon black Acetal. Frame: Cheeks: Toughened, glass fibre reinforced Nylon. Load straps and ball bearings: Grade 316 stainless steel. Integrated stainless steel hub to accept lashing attachment and through-sheave Becket. Suits up to 4mm lashing. Includes 750 mm (30") x 1.7mm ? lashing cord. Dimensions: Sheave ? 20 mm Max. Rope ?: 4-6 mm