C.H. Yates Rubber 440R 4" Marine Rocker Roller with 3/4" ShaftRibbed Wobble Roller - Black Designed to wobble back and forth, to automatically adjust to the contours of your boat. Length: 4-1/4" Outside Diameter: 4-1/4" Shaft: 3/4"Features of C.H. Yates Rubber 440R 4" Marine Rocker Roller with 3/4" Shaft High grade rubber construction | Automatical..