Weaver's top mount base is machined to tight tolerances for a custom fit.It offers maximum strength for rings to hold tight and is constructed of aluminum.Fits marlin 88/89/98; compatible rear bases for remington 121 w/13/16" diameter barrel/12c w/octagonal barrel/25; stevens 416.Type: 1-Piece BaseModel: Top MountStyle: Top MountMisc: N/AFinish: BlackMaterial: AluminumPieces: 1Gun Type: RifleRings Included: No