Femometer Smart Ring Gen1 for Female Fertility sells on Amazon. I think the price is very good. Please read some of the reviews and see people thought of the product.**If you’re not sure whether to buy, add to cart, and you can come back to it later!**

Size Before You Buy – Before purchasing a femometer ring, we recommend try to determine the best size for your finger. It’s the ideal way to find the perfect size
Technical Support – For Android users, please search and download “Femometer Connect”. For iOS users, please search and download “femometer”. Note: No Additional fee for subscribe, menstruation, and sleep tracking features