This is the standard size for an 8 inch Boat Trailer Keel Roller made of a Yellow PVC (polyvinyl chloride) material that will not dry rot in the sun like rubber and won't mark your boat like standard black rubber rollers. The Center Bore has 2 bushings in it which have a center diameter of 5/8, so you would need to use a 5/8" Roller Shaft with this roller. This Roller is Reinforced by an Aluminum Core which will not rust or corrode and helps the roller to spin on the Roller Shaft, further assisting in Loading and Unloading the Boat to the trailer.
Fits Standard 8 inch Roller Brackets
Will not Mar or Scratch your Boat or PWC
5/8 inch Center Diameter
Yellow UV Resistant PVC