Extremely low profile, fixed fairlead block keeps control lines and halyards close to the deck. The hinged version is for mounting on spars or on deck. It adjusts to variable halyard and control line angles to provide a proper lead, and its narrow base plate allows multiple mounts. Both have open race ball bearings to allow salt, dirt and debris to be easily flushed out. Configuration: Lead block Sheave: UV-stabilized white Delrin Ball Bearings: Delrin Sheave Size: 1-1/16" (27mm) Line Diameter: 5/16" (8mm) Cheek Material/Finish: Polished stainless Safe Working Load: 500lb.