The pulley wheels are made of aluminium alloy / MC nylon mounted on ball bearings; the groove is lined by a neoprene ring or by wear-proof interchangeable nylon or aluminium wheels. The frame is
made of galvanized steel. The pulleys can be supplied with three types of connections: fixed(B), swivel-type(C) or with a hook supplied with safety lock(D). Grounding device or complete conductive
sheaves can be supplied on demand.