Harken's 57mm Carbo Air Block with Swivel (Part No. 2600F) features a 57 mm sheave diameter (2 1/4 in), a maximum line diameter of 10 mm (3/8 in), and a maximum working load of 359 kg (792 lb). These low-friction blocks are renowned for their lightweight design, durability, and affordability. Paired with the popular Harken Big Boat blocks, they offer high working loads for effortless and secure trimming.