55 Series Orbit Block™ Ratche Single Fiddle Block with Becket & Shackle for 3/8 mm Lines by Ronstan®. Automatic ratchet block. Now you can enjoy the flexibility of setting up your ratchet blocks to suit yourself. Ronstan is the only company that offers a ratchet block with both auto and manual engagement modes*. In the auto mode of the ratchet mechanism engages when load is applied, but switches off when it's released. This lets the sheet run out smoothly and freely-great for rapid easing of the sheet and for gybing asymmetric spinnakers. In manual mode, the ratchet mechanism can be switched on or off as required. This is the preferred mainsheet set-up for may top sailors. Try the block in both modes and see which you prefer - you really can't go wrong. If this product is out of stock please contact [email protected] and we can advise on availability.  Sheave Ø 55 + 35 mm Max. Rope Ø 3/8 mm Max. Cable Ø mm Pin Ø 5 mm M.W.L. 250 kg B. L. 750 kg Weight 112 g