Free shipping
30-day returns
No subscription
Sizes US 6-14
Aluminium alloy
Multi-day battery
Free shipping
30-day returns
No subscription
Sizes US 6-14
Aluminium alloy
Multi-day battery
Free shipping
30-day returns
No subscription
Sizes US 6-14
Aluminium alloy
Multi-day battery
Free shipping
30-day returns
No subscription
Sizes US 6-14
Aluminium alloy
Multi-day battery
Free shipping
30-day returns
No subscription
Sizes US 6-14
Aluminium alloy
Multi-day battery
Free shipping
30-day returns
No subscription
Sizes US 6-14
Aluminium alloy
Multi-day battery
01 — Size it
Wrap a strip of paper around the base of your finger, mark the overlap and measure it against our chart. Two minutes now saves a fortnight of shipping later. Sizes run US 6 to 14.
02 — Wear it
Pair it once with the free app, then forget about it. Index or middle finger, day and night. It handles handwashing, sweat and rain without complaint.
03 — Read the pattern
One night tells you almost nothing. Eight weeks tells you a lot. The app shows how your sleep, heart rate and activity trend over time, and gives you one readiness score each morning: push today, or ease off.
Questions people ask
How do I know my ring size?
Wrap a strip of paper around the base of the finger you'll wear it on, mark where it overlaps, and measure that length in millimetres against our chart. Measure at the end of the day, when your fingers are at their largest, and measure the exact finger you plan to use. Sizes run US 6 to 14.
What if I order the wrong size?
Message us within 30 days and we'll arrange an exchange. Sizing from a chart is genuinely hard to get right and we don't hold it against you.
Is there a monthly subscription?
No. The companion app is free on iOS and Android with no membership fee. You buy the ring once and that is the end of it.
How long does delivery take?
Typically 10 to 16 business days within the US, with free shipping. We ship directly from our manufacturing partner, which is what keeps the ring at $49.95 in a category where comparable devices cost several hundred. The trade-off is a longer wait, and we would rather say so here than bury it at checkout.
Is it a medical device?
No. ARO One is a general wellness and fitness product. It is not intended to diagnose, treat, cure or prevent any condition, and its readings are estimates for spotting trends rather than clinical measurements. If anything about your health concerns you, speak to a qualified healthcare professional.
Can I wear it in the shower?
Yes. It handles handwashing, sweat and rain without trouble. We don't recommend swimming laps or sitting in a hot tub with it.