Lightweight, strong, reliable, and affordable, the Harken 57mm Block with Swivel (Part No. 2600) features a sheave diameter of 57 mm (2 1/4 in), capable of supporting a maximum line diameter of 10 mm (3/8 in). With a maximum working load of 359 kg (792 lb), these low-friction Carbo Air blocks act as perfect companions to the popular Harken Big Boat blocks, providing high performance and safe trimming for a wide range of applications.