With more than 100 years of impeccable performance, the Fulton line of trailer jacks, winches, and couplers has become the industry standard for light and medium-duty trailering. Suited for all environments, Fulton performs best when the weather is at its worst.• Compatibility: 3-1/8 Inch Hub Diameter• Quantity: Single Dust Cap For 8-Bolt Hubs 3.125 Inch Hub Diameter Limited 5 Year Warranty | Fulton Trailer Wheel Bearing Grease Cap, 3.125 Inch Diameter