Simple to read . I check my oxygen often. You don’t want it below 90. You just place your finger. In it and turn it on it will show you your oxygen level and heart rate.

Yes. I have them all over my house and on my purse. I know the feeling I get when my O2 is low now so I sit down and do pursed mouth breathing to get my O2 back into the 90’s. If you do not know the technique. It is slow breathing. Slow Deep breathe in through your nose and blow out through your pursed lip mouth. I watch my O2 meter and keep this going until my O2 is 92 or above. Helps me every time! Good Luck! 😎

I have a portable it’s a lot better than tanks

I use one all the time. I have one that I put on my finger every night to register when my O2 drops while I'm asleep. I even sleep with a bipap and my O2 still drops to between 88 and 90

I took an overnight oximetry test which showed I spent 4 hours at 82. So I’m on nighttime O2 also. A follow up test showed I spent 20 minutes at 87 but most of the rest of the night I was good.