Mr. Gasket 5970 Ultra-Seal Collector Gasket Product Features Graphite-impregnated material resists heat and pressure Ultra-seal gaskets are reusable Applicable for hush thrush muffler #510 Bolt diameter is 2-3/4, bolt circle 3-1/2, and bolt hole 3/8 Steel core adds strength Product Specifications Brand: Mr. Gasket Item Weight: 1.6 ounces Product Dimensions: 5 x 4.4 x 0.1 inches Item model number: 5970 Manufacturer Part Number: 5970 OEM Part Number: 5970 Shipping Weight: 1.6 ounces Date First Available: July 9, 2007 Why you Should Buy from Us? Trusted Seller, Great Feedback Quick Shipping and Tracking HUGE Discounts Excellent Returns Policy The BEST Customer Service Shipping & Returns We Ship Worldwide! 14 Day Money Back Return Policy Items Ship within 24-72 Hours Shipping process begins as soon as you order. We cannot cancel orders. Our goal is FAST delivery! Product Description Mr. Gasket Ultra-Seal Collector Gaskets feature a steel core for strength and a graphite-impregnated material that resists heat and pressure. Gaskets conform to the flange for a superior seal. The inside diameter of the gasket is 2.75". The graphite means the gaskets are easier to remove, too. Ultra-seal gaskets are reusable. Hardware is not included with this kit. Ultra-seal collectors gaskets are sold as a pair. Thank You For Your Business!