Mares Proton Purge Cover by James1979
Purge Cover needs to printed in a flexible filament (TPU or TPE) and works best with the original retaining ring from the regulator. If the original retaining ring is toast, there are 3 versions of the retaining ring (they should be printed in ABS or PETG).
www.thingiverse.com
@James79 I do, the interior parts shouldn't be a big deal as it wouldn't be seen. Any who, thanks for reaching back out!