DoubleStar Bolt Rebuild Kit Black. Specifications for DoubleStar Bolt Rebuild Kit: Manufacturer: DoubleStar Color: Black Gun Make: AR Platform Gun Model: AR-15 Gun Type: Rifle Package Contents: DoubleStar Bolt Rebuild Kit 1 Extractor 1 Extractor Spring with Bumper Pad 1 Set of 3 Gas Rings 1 O Ring 1 Extractor Pin What firearm models does the manufacturer say DoubleStar Bolt Rebuild Kit is compatible with? The manufacturer says that DoubleStar Bolt Rebuild Kit is compatible with AR-15DoubleStar AR790: Bolt Rebuild Kit Black