The Apple Watch Series 6 feels like it has perfected many of the features I liked about its predecessor. It has a brighter always-on display, a more powerful processor, faster charging and two new colorful options to choose from. But the feature I was most excited to try out was its new sensor that measures oxygen saturation in the blood (aka SpO2) with the tap of a screen. As someone who panic-bought a pulse oximeter at the start of the coronavirus pandemic and still checks her levels at the first sign of a cough, the thought of having one strapped to my wrist at all times was enough to pique my interest. But unlike the ECG feature on the Apple Watch, which has been tried, tested and cleared by the US Food and Drug Administration, along with the irregular heart rhythm notifications, SpO2 on the Apple Watch still seems to be in its early stages. Navigating all this new data can be daunting for anyone who's not a medical professional.