Luna Smart Ring Gen 2 vs RENPHO LYNX: which should you buy?

The RENPHO LYNX is our pick, but there is no real difference between these two rings for most people. Both track sleep, activity and cycles with no monthly fee, and both work with an iPhone and with an Android phone. The RENPHO LYNX gets the nod because it is the cheaper ring today.

Who should get the RENPHO LYNX

Get the LYNX if you want to try a smart ring with no monthly fee and no fuss. RENPHO sells it with no subscription and a charging case in the box, and its free app includes cycle tracking. It works with an iPhone and with an Android phone.

Who should get the Luna Smart Ring Gen 2

Get the Luna ring if cycle tracking matters to you. Luna uses temperature and heart rate variability for menstrual and ovulation tracking, with Clue sync and no monthly fee. It works with an iPhone and with an Android phone, and it charges nothing extra for size or color.

The differences that matter

Neither ring leads on sleep tracking, battery life or comfort in our comparison. When two rings are this close, price and fit should decide.

The Luna ring leans further into cycle and fertility tracking, with Clue sync. If that is your main reason for a ring, it can be worth the extra money.

A ring is the quietest way to track sleep: no screen, nothing on your wrist, and nothing to wake you. Get your size right before you order, because a ring that sits loose reads poorly. Most makers send a sizing kit first, and it is worth the wait.

Price and value

Today the Luna Smart Ring Gen 2 costs $249 (checked Nov. 2, 2026) and the RENPHO LYNX costs $179.99 (checked Nov. 2, 2026). The RENPHO LYNX is cheaper by $69.

If you just want a good ring, pick the RENPHO LYNX and keep the difference.