This is the eBay link for the following FM Lens
http://www.ebay.com/itm/FM-Lens-Variable-Diopter-W-Moller-Anamorphot-32-2x-For-Single-Focus-Anamorphics-/182432011462?
This is an FM Lens rig with a Moller 32/2x anamorphic lens installed within the FM module. It's sometimes called a variable diopter and other companies make versions such as the Recrilux 3ff, Coredna, and Dslr Magic Rangefinder.
This item is not available to buy through FM lens directly any longer and I barely have seen any variable diopters other than the Rangefindee for sale new or used for over a year.
T