Kibblewhite Manganese Valve Guide For Harley Features: Precision-machined guides Manganese-bronze guide material is softer than nickel aluminum bronze valve guides Excellent heat conductivity which promotes long valve life Guides can be easily reamed with a battery-operated or electric drill and finished with a high-quality ball hone Eliminates the need for expensive honing equipment that would be required for nickel bronze valve guides Machined to accept OEM and aftermarket seals Inside Diameter: 0.3760 Outside Diameter: 0.5650 Sold individually Made in the USA