Cat. No. 98955
This is a part that allows you to mount digital backs and other things straight to the back of the X-Act2. It has a round mount like the lens panels that fits the rear standard of the X-Act2 (and also the BalPro) on one face and on the other it has a receptacle that takes and locks in the different digital back adapter plates. I currently have one such adapter plate for the Hy6 digital backs available separately. It have been told but not yet confirmed that the Alpa plates will fit this.
