https://www.amazon.com/Zacurate-Fingertip-Oximeter-Saturation-batteries/dp/B016J60WB0
https://www.beyondmedshop.com/products/500dl
https://cdn.shopify.com/s/files/1/0641/4457/files/Acc_U_Rate_500D_English_Manual_Version_1.2.pdf
Normal SpO2 values vary between 95 and 100%.