Black Aces Tactical Rail Features: - One piece T6 6061 construction. - Weighs 14 ounces. - Type 2 black anodizing. - Includes installation tools and instructions. - Serial number remains visible. - No gunsmithing required. - Rail will fit tapped and untapped receivers. - Install time takes under 10 minutes from the time the rail is removed from the box to the time the shotgun is ready to fire. - 500 models should be the fitted with extension tubes and bayonet lugs. - 590A1 should be lightly narrowed for the best fit. - OEM heat shield should be removed as our rail replaces it. - We recommend an 18 inch minimum barrel length. - Made in America.