40mm Carbo Air Double Swivel BlockLow-friction Carbo Air blocks are lightweight, strong, reliableand affordable. Companions to the popular Harken Black Magic block line, these small, compact blocks have very high working loads for safe, easy trimming.Specifications:Sheave (mm)40 mmSheave (in)1 9/16 inMaximum line (mm)10 mmMaximum line (in)3/8 inMaximum working load (kg)440 kgMaximum working load (lb)970 lb Quick Guide (pdf)