The Harken 57mm Carbo Ratchamatic Block with swivel and becket, in red. The Ratchamatic is a load-sensing ratchet block: it rolls freely in both directions at low loads and engages the ratchet automatically as load builds, switching seamlessly between ratchet and light-air modes. It has 10:1 holding power and takes lines up to 10 mm (3/8 in).
