Rear Converter Lens for C-mount lenses, 2x This is a 2x rear converter lens for use with C-mount lenses such as: C-mount macro zoom lenses, C-mount telecentric lenses, C-mount fixed focal length lenses, C-mount varifocal lenses, etc. When placed between the camera and the lens, the magnification becomes 2x. ~Important Notes~ This cannot be used with lenses that extend towards the camera for focus adjustment. This listing includes: 2x Rear Converter Lens body, Lens cap for the top side, Lens cap for the bottom side. Operation confirmed. Instant purchase is OK. I have a total of 4 of these, although they are from different manufacturers and different LOTs. All are 2x magnification. If you want multiple units, please comment beforehand and I will accommodate your request.