I purchased and wear a full time on the spot oximeter ring-the alarm goes off when I get below 88%-so I slow down and relax until it goes off. It's a Wellue and costs $159. I've had it for over a year. Also hooks up with your iPhone and records. The other ones are not set up to alarm and you have to wait for a reading. I found this by accident and am not a commercial, just a guy with COPD from covid.