Nonin Digital Finger Pulse Oximeter 
Nonin finger pulse oximeter Slightly larger than a standard finger probe, the Onyx is the only self-contained finger sensor pulse oximeter on the market. Small and light-weight, the Onyx is perfect for spot check of Spo2 or short term monitoring. Featuring automatic operations and bright LED that provides SPO2 level and heart rate. Operates 12 continuous hours on two AAA batteries.