I agree with Frank above. I'm interested if the external dimensions approximate the original MKII(s) suppressor.
As with all things, this interest is variably dependent on price point.
For those interested, these work VERY well. I've taken mine (NOT FS) out on several occasions and reliably fired the full drum with a single trigger pull. Very fun.
I have an M11 and love it, but you have to know what you are getting into.
I recently bought an UZI and it's really been growing on me. I can't seem to miss with that thing. Also, it sounds amazing with the MK9k/Phoenix on it.