Composite Idler Sprocket with Bearing Bore Diameter 17 mm Chain Number 60 Sprocket Material Fiberglass-Reinforced Nylon Number of Teeth 13 Outside Diameter 3.52 in Bearing Material Chrome Steel Bearing Number 6203-2RS Bearing Type Ball For Use With Sprocket Assemblies T-Max Tensioner Hub Diameter 1 3/4 in Length through Bore 1 in Lubrication Mobil Polyrex EM NLGI No 2 Material Grade 6/6 Maximum Operating Temperature 225 Degrees F