What does the oxygen saturation clip check?

You're asking what oxygen saturation clips check, right? Oxygen saturation.

Oxygen saturation clip is a medical device used to measure oxygen saturation. The principle is to use light-emitting diodes to emit red and infrared light to detect the body's oxygen saturation and pulse rate through the brightness of finger skin and musculoskeletal tissue.

Keeping an oxygen binder (oximeter) at home is mainly for the elderly. Be alert for values below 90 and seek medical attention quickly for values below 85.