Used: Rolleiflex behind the lens M39/M40 shutter adapter
This is rare, no longer produced accessory for the Rolleiflex 6000 and Hy6 system cameras that enable you to mount a number of different lenses. Originally made for the Schneider M-Componon Macro lenses (28mm, 50mm, and 80mm) this adapter also was employed to fit the Rodenstock Imagon lens as well. This has a m39 (Leica enlarger style) screw mount with a full PQ shutter all in a helicoid type extension with 11mm of travel.
Condition is excellent and this has been fully tested for function. Comes with the often missing 40mm adapter ring, both caps, and original box (the box is somewhat damaged, however).
I use this adapter to fit mostly macro lenses such as the Rodenstock APO 90mm and 105mm Rodagon lenses but with the RMS adapters you can also fit Zeiss Luminar lenses or Leica Photar lenses.
Naturally, this works by itself or in conjunction with the other extension tubes - even the bellows for ultra high magnification. You can fit this to your X-Act2 using the Rollei lens adapter.
These are hard to find used - I keep two in my personal collection. I have asked the factory to consider remaking them, but for now - you have to find one second-hand.