Does anyone know where I can get what looks to me like an adjustable cheek spacer for the TRG? It has like a weird know right under the cheek piece. It looks like you an tighten and loosen it from this without actually using tools. Anyone know where I can get one of these? Unfortunately, I am having a hard time figuring out what size spacer I need. I had one that was .64" but I believe it is too high.