Used extensively for sheet blocks on small to mid-sized keelboats and as control line blocks for larger offshore boats. Suitable as mast-base or lead blocks on small to mid-sized boats. Universal three-way head. Black anodized aluminum or stainless cheeks. Stainless straps and posts. Sheave: UV-protected Delrin Ball Bearings: Plain bearings Sheave Size: 2" (51mm) Line Dia.: 7/16" max. Cheek Material/Finish: Polished stainless or anodized aluminum, stainless strap Shackle/Strap Type: Swivel with three-way locking Cleat: Fast-entry cam cleat Safe Working Load: 1,750lb. (*1) Requires four #10 RHMS (*2) Tuflite pad for 504-11 cheek fits 2-1/2"-6"dia. spar sections