Extension Sling allows the installer to get around those big trunked trees. Slings available for Fun Ride Deluze (31-00015) and Super Z (31-00017). Made from Galvanized Aircraft Cable (GAC). Aircraft cable is strands, cords and wire rope made of special-strength wire, designed primarily for use in aircraft industry and military applications. These are 7x7 GAC replacement cables for the Fun Ride zip lines. The 7X7 GAC is durable, highly flexible and abrasion resistant. It's general purpose is for strength, flexibility and tensioning. Message when checking out as to which model is needed. Total length of cable including loops is 121cm.