Step Down Up Adapter Ring M42 to M39 42mm to 39mm Leica Lens Pentax Camera Body

M42 to M39 step down adapter ring (can also be used as M39 to M42 step up ring). M42 to M39 step down adapter ring. - Female thread: 39mm on interior rim. - Male thread: 42mm on exterior rim. We specialise in digital and electronic products.