They certainly seem very popular, so theres loads of support out there.
Loads of upgrades for it too.
I use an anycubic mega s, which coming up to a year of a lot of use, has been practically faultless.
They look like 2 x standard foster male type couplers along with a us type 1/8 npt nipple on the end of the line.
check out the fittings section on highpressureairsoft as they usually have a good selection.
One question i have in regards to the mp5 sd- Have you ever tried unscrewing the end caps on the suppressor tube?
It looks like they come off, but im not sure! I'll 3d print some barrel stabilisers for it if so.