MH offers O2D2-compatibility solutions for built-in O2 systems
They offer
this stuff, but the MH website doesn't seem to mention FAA approvals.. Not sure how you will install it (legally) in a CofA plane. Perhaps you don't and this is for LSA/Exp only.
The O2D2 is just a portable-system item.
Perhaps the unidentified "blue mask" was the MH mask for use with the O2D2?