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. We aim to ship pre order Harken parts within one week of purchase.  Sheave Ø (mm)40 mm Length (mm)70 mm Weight (g)48 g Maximum line Ø (mm)10 mm Maximum working load (kg)220 kg Breaking load (kg)735 kg