BabyO2 Baby Oxygen Monitor Foot, with Alarm in APP, Track O2 Level & Heart Rate, Wearable Blood Oxygen Saturation Monitor Bluetooth (for 0-3 Years Old) 3.9 out of 5 stars 317 $149.99
https://www.amazon.com/Owlet-Smart-Monitor-Oxygen-Heart/dp/B08BT6QMN5