Informaation about o2

HELLO EVERYONE
JUST WNATED TO KNOW HOW MANY PEOPLE ARE ON O2 AND WHAT KIND OF SYSTEM YOU HAVE . MY DR. I SEEN HIM ON JULY 3rd IS PUTTING ME ON O2 JUST WANTED TO SEE IF ANYONE HAD ANY INPUT ON THE O2 SUBJECT MY INSURANCE IS SAYING GO WITH A PORTABLE CONCENTRACTER BUT I’M NOT SURE WHICH WAY TO GO.
HAVE A GOOD DAY BRENDA