The Cambo Uni-Track Rubber Tube is a part of the Uni-Track Dolly Kit. You can extend the Dolly Track System by replacing it with the Cambo Uni-Track Rubber Tube.This rubber tubing can be used with the hardware of the Cambo Dolly SystemThe dolly can be moved effortlessly on itThe Cambo Uni-Track Rubber Tube provides adjustable system configuration