This adapter will allow you to use 3M cartridge filters with an MSA respirator.
The seal feels secure enough to me, but use at your own risk.
I recommend printing on its side as I've oriented it, with support material.
100% infil, PETG, ABS, or above.
Do not print flat: the plug was to weak to handle the resistance of locking it in to the 3M filter because of the layer line orientation.
Delores seems to approve.
print sideways with supports for best strength.