Control loaded lines with ease. 57mm Carbo Ratchamatic® Double Block is adjustable for use in many applications and weather conditions. This load-sensing ratchet block rolls freely in both directions under low loads, and then engages the ratchet automatically as loads increase. With 180-degree wrap, you get 10:1 holding power. Great for asymmetrical spinnakers when you need tough holding power and a quick release. Features Hardkote anodized eight-sided aluminum sheave, engineered plastic ball bearings in fitted ball races and long-glass reinforced engineered nylon cheek material.