SEcond one I have owned. Very reliable and seems to work as it should. Doctors office uses same one. Very simple to use and battery easy to change- the batteries last a long time.
This ADC Pulse Oximeter is extremely accurately calibrated when compared with the gold standard high quality hospital oximeters. Accuracy to within + or - 2% at or above 80% O2 saturation and to within + or - 3% accuracy below 70 % O2 sat is very important for saving lives. The Chinese knockoffs and no-name brands can give a false sense of security/safety, since their accuracy is questionable at best, especially at levels below 95%. Those can often keep reading 95% O2 saturation when in fact the individual's levels are at dangerously low levels below that - I am not a sales person for ADC, which is New York based - Just an appreciative customer.