The stock is compatible with MD-20 drum magazines and with the Ultimak gas mounted picatinny rail (as seen in the photo).
The KUSHNAPUP LLC is taking preorders for the stock. The preoder price is $200 but this will increase to $450 after the preorders close. I asked Bjorn, the founder of the company, when they will begin shipping and he said 3-6 months depending on how many orders are placed.
