OPF series, single web block, sheave Ø 50, SWL 600 kg   New by Antal theOne Piece Frameblock, the block without pins or screws, it is a light and strong solution: simply a hard black anodized and teflon coated aluminium frame in one piece. A complete range from 50 to 140 mm sheaves in single, double, triple, fiddle, and deck versions, for webbing or shackle connection. Sizes are based on the range of HR shackles available and on their safe working load (SWL). The HR swivel head. Made in high resistance s.steel, with three positions: swiveling head, longitudinal lock and transversal lock. HR shackles included. The one-piece-frame. The one-piece aluminium extruded body is the strongest and lightest solution, no assembling pin rivets or screws and nuts. CNC machined - polished - hard black anodized and teflon coated. The composite fibre sheave. The resin (aluminium on larger mod) sheave runs on the main Composite Fibre bearing and on a ground s.steel hub: low friction highloads - n