Midrange Captive Ball traveller 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. The 1624 car has a shackle for block attachment and screws to mount old style control blocks as used on non captive ball bearing cars.