As you may be aware, if you want to run compact gearing, or BMX gearing on a fixed gear, you need a tiny cog. When you’ve got a tiny cog, your lockring is tiny. Once a cog gets to a certain size, it can’t go any smaller because of the diameter of the threading on the hub.
Maybe this fixes it? No idea. Either way it looks like a prototype, so don’t get too excited!
Head over to their site to see the assemblage pictures.