Dragonfly Optical High Quality 49Mm - 58Mm Male-To-Male Coupling Ring Adapter Used For Lens To Lens Coupling To Create Extreme Close-Ups High Quality 49mm-58mm Aluminum Male to Male thread Used for lens to lens coupling to create extreme close-ups This adaptor requires two lenses to function How to Use: one is attached, as normal on the camera the other is reversed on front of the camera lens. The ring screws into the filter thread of both lenses when you go to mount them together Made of metal (not plastic)