Excellent condition. I have each size sock available. The largest sock is a little more loved, as you can see from the photo, because this was the one he was using as he started walking. And we would always just leave it on after nap or what not. You can also purchase the socks through their website, if you would like to replace it, it works perfectly fine though, there is no need to replace it.
Here is the description from their website:
The Smart Sock comfortably wraps around your baby’s foot to track heart rate, oxygen levels and sleep using clinically-proven pulse oximetry. The base station glows green to let you know everything is okay but notifies with lights and sounds if heart rate or oxygen levels leave preset zones.

Parents can see live readings using Owlet’s app.
Cross posted.