Doesn't work – Vigor SpO2 | Pulse Oximeter for Sleep Apnea, Asthma, and Blood Pressure Review

This app yields an acceptable margin of error. What reads as 98% on a reliable device reads between 48 and 52% on this useless app.
Review by I am a user tads on Vigor SpO2 | Pulse Oximeter for Sleep Apnea, Asthma, and Blood Pressure.