Spuhr is bringing in their HK collapsing stock. It has been used by Swedish Home Guard.
As you can see above, there is one for a G3 and below is one for an MP5K.
The stock rides on a short custom buffer tube. The stock has a non sliding cheek rest that they are going to modify to be quick detach. At the moment you can only use this stock with red dots. The cheek rest sits to high to utilize the iron sights.
Along with the stock, Spuhr is making this NVG bridge in conjunction with Wilcox. Each side can be quickly removed so the user is not limited to use both optics.
Here is their Benelli M4 handuard.
This is a 3D printed prototype handguard that was made for the HK417.