LOADRITE 2-Wheel Wobble Track Roller Assembly.2- Wheel left or right mount, Adjustable from 15" to 19" centers, fits 3" pivot bars. Has 1-1/8" DIA aluminum bars that pivot left to right on 1/2" center mounting u-bolt and pivot plate (included).YATES 5" x 3" non-marking yellow TPR rollers with smooth Delrin bushing so no metal to roller contact for less drag.Sold as each