Antal OPF series is a new light, strong one piece frame block, without pins or screws. It is a hard black anodized, Teflon coated aluminium frame. The resin sheave runs on the main composite bearing and on a ground stainless steel hub meaning low friction highloads and no lubricant is required. The HR Swivel Head is made in high resistance stainless steel, it can be placed in three different positions; swivelling head, longitudinal lock and transversal lock. The one piece frame is made from aluminium, pin rivets, screws and nuts are not required for the assembly.