Poly vinyl rollers are long-lasting and will not mark or mar your boat. When replacing wobble rollers, consider the width, diameter, shaft diameter and bearing length (length through the middle). Remember to order replacement washers and hog rings when installing new wobble rollers. Wobble kit includes: (4) wobble rollers with 1-1/8" bore, (4) 7/8" bushings, hog rings & washers.