Universal head allows one block to function as a front shackle, side shackle or swivel shackle block. Large sheave diameter and high working loads make them suitable for sheet and control blocks on medium to large offshore boats. Beckets are removable. 704 series are aluminum; 705 blocks are stainless. Where applicable, blocks use 1/4" fasteners. Sheave: Black or white Delrin Bearings: Plain bearings Sheave Size: 2-3/8" (60mm) Line Dia: 1/2" max. Shackle/Strap Type: Swivel shackle with three-way locking head Cleat: 704-75, 705-75 = stainless Sure-Grip cam Safe Working Load: 2250lb.