Ronstan RF56101 Orbit Ratchet Block. Designed for applications where weight is of paramount importance. The securing loop is easily changed and we suggest that you use either a forged eye or shackle to secure the block as pressed steel fittings can be sharp and will prematurely wear the rope mounting. Features: Automatic and Manual ratchet in one block Up to 20:1 holding power Easily fitted and securely retained Dyneema Link head Smooth easing of sheets High performance cleating Technical: Sheave Diameter 55mm Maximum Rope Diameter 10mm Maximum Working Load 250kg Breaking Load 500kg Weight 78g Materials: Ball bearings - High compression strength carbon black Acetal Stage 2 bearing - Carbon fibre reinforced, PTFE impregnated Nylon Frame/Cheeks - Toughened, glass fibre reinforced Nylon Rope Link: UV stabilised, multi-strand impregmented SK75 Dyneema Applications: Mainsheet systems on dinghies Spinnaker sheets on dinghies Control line applications on larger yachts Some RT Orbit Blocks™ can be set to Automatic mode or Manual mode to suit the application or user’s preference. OPERATION MANUAL MODE RT blocks leave the factory in Manual mode, with the black MODE switches on both sides of the block positioned away from the red ON/OFF knob. Use the red ON/OFF knob to turn the ratchet ON or OFF. AUTO MODE With the block in Manual mode, turn the ratchet off by rotating the red ON/OFF knob to the OFF position. Slide the black MODE switch firmly toward the red ON/OFF knob until it locks into the recess in the knob. Repeat with the MODE switch on the other side of the block. The block is now in Auto mode. To return to Manual mode, slide the black MODE switches on both sides of the block firmly away from the red ON/OFF knob. Now use the red ON/OFF knob to turn the ratchet ON and OFF. We recommend using the RF613S shackle to securely attach the block to the existing deck eye on your boat. This helps the block maintain maximum freedom of movement and reduces the risk of wear on the Dyneema loop due to sharp edges on the deck eye, then use the 8072 Rubber Boot to keep the block upright and provide a neat finish. See related items.