Low-friction Carbo AirBlocks® are lightweight, strong, reliable—and affordable. Companions to the popular Harken® Black Magic® line, these small, compact blocks have very high working loads for safe, easy trimming. This ultra light weight block is perfect for mainsheets and control lines for small dinghies like Optimists (Optiparts number EX1308). These blocks can be used as becket blocks too.   Sheave Ø (mm)40 mm Length (mm)64 mm Weight (g)40 g Maximum line Ø (mm)10 mm Maximum working load (kg)220 kg Breaking load (kg)735 kg