The Harken 40mm Triple Ratchet Block Swivel, Becket, Cam Cleat, 29mm Block allows for sailors to easily grip lines under pressure while balancing between securing power and controlled release. With a maximum line diameter of 5 mm (3/16 in) and a maximum working load of 408 kg (900 lbs), this block is perfect for various sailing needs. Part No. 2619 boasts a 40 mm (1 9/16 in) sheave diameter for smooth movement.