45mm Auto Ratchet Block used for the Spinnaker Sheet on the RS Quest. Attaches to the Shroud Eye Bolt using a D Shackle. The part numbers for the eye bolt and shackle are QUE-HF-304 and A-621104, respectively. The sheave automatically changes from free-turning ratchet when the load increases. The sailor decides when the automatic ratchet kicks in. The switch over point is set using an all key to adjust a screw inside the sheave. Sheave diameter: 45mm. Safe Working Load: 330lbs. Breaking Load: 661lbs. Max line: 10mm. Shackle: 4mm.