This listing is for a Kiron reverse mate for reverse mounting a lens with a 55mm filter thread for taking close-up (macro) pictures with a Kiron 24mm f2.0, 28mm f2.0, 28mm f2.8, 80-200mm f4 lens as well as other lenses with a 55mm filter thread.  This reverse mate fits on a Pentax K1000, K2, KM, ME, MV, MG bayonet mount single lens reflex film camera.