This one-piece aluminum base is machined to tight tolerances for a custom fit.It offers maximum strength for rings to hold tight.Screws are included.Fits- cva round barrel/receiver (post '96 model); traditions in-line muzzleloaders w/round receivers; winchester x-150 apex muzzleloaders.Type: 1-Piece BaseModel: Top MountStyle: Top MountMisc: N/AFinish: SilverMaterial: AluminumPieces: 1Gun Type: MuzzleloaderRings Included: No