Harken Midrange Captive Ball Traveler Cars are built to handle high loads on boats from 27 ft to 34 ft (8 m to 10 m). The one-piece solid aluminum construction is lightweight and strong. Machined aluminum Hardkote-anodized races permit Torlon® bearings to transition smoothly from the active to return race. Stainless steel wire guides keep the balls captive. Harken Shackle Cars have low pivot points to handle non-vertical loads.