New Oura Smart Fitness and Health Tracking Ring Gen. 4, Silver color.

$250

I will order the size that you choose. I haven't selected a size yet, though it's been paid for. I've never been one to wear rings and have decided not to start.

Made from polished non-allergenic titanium, on inner and outer surfaces. Includes charger and cable. Water resistant to 100m. (See images and tech specs on Oura website.)

Note: After the first month, there is a $6 per month subscription to get full app features. Otherwise, features in the app are limited, though I understand that it's possible to download the ring's data to a spreadsheet for free and use how you would like.

$250