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 39a; moss 43, 44, 144, 46bt, 35, 45, 46; sav 19, 23, and winchester 75 target; rear bases compatible with moss 40 and sav 3; front and rear bases compatible with sav 93f w/heavy barrel/93, 93fvss, 93r17, mark ii/64/cub.Type: 1-Piece BaseModel: Top MountStyle: Top MountFinish: BlackMaterial: AluminumPieces: 1Gun Type: RifleMount Type: ScrewsRings Included: No