● Unreleased — Launching Fall 2025
ARC is a 2.9-gram titanium ring that reads your sleep, heart rate, and recovery — then gets out of the way. No screen. No noise. Seven days on a charge.
Titanium · 2.9 g · 100 m waterproof · 7-day battery
01 — The Object
Grade-5 titanium, machined as one piece
Weight
2.9 g
Lighter than a wedding band. You will forget it exists — that's the point.
Sensors
3 arrays
Infrared photoplethysmography, skin temperature, and a 3-axis accelerometer — inside 2.4 mm of wall.
Finish
PVD matte
Physical vapor deposition coating, scratch-tested against keys, kettlebells, and rock faces.
02 — Sleep
ARC samples your heart rate, HRV, and skin temperature every second you're asleep — then maps light, deep, and REM stages against your own baseline, not a population average.
Light, deep, and REM — resolved from cardiac and motion signatures.
Wake events and restlessness, weighted by when they happen in the night.
Your circadian window, learned over two weeks and refined nightly.
03 — Readiness
Overnight HRV, resting heart rate, temperature deviation, and sleep debt — compressed into a single readiness score. Push when it's high. Recover when it isn't. No guilt, no streaks, no gamification.
04 — Battery
A full week of continuous tracking on one charge. When it's done, the wireless charging dock takes ARC from empty to 50% in four minutes — about the length of a shower.
Continuous sensing, all week, on a cell smaller than a coffee bean.
Drop it on the dock. 0–50% in four minutes, full in forty.
The dock is the only accessory. USB-C in, ring on top. Done.
05 — Specifications
Titanium
Grade-5, one-piece
2.9 g
Total weight
100 m
Waterproof
Qi wireless
Charging
7 days
Battery life
8 sizes
US 6 – 13
A note on proof
ARC hasn't shipped yet, so you won't find reviews here — real or otherwise. What we have is three years of engineering, four hardware revisions, and a ring we wear every day. The reviews come when you write them.
— The ARC team
06 — Questions
Every waitlist order ships with a free plastic sizing kit first. Wear your best-fit sizer for 24 hours — fingers change size overnight — confirm in the app, and your ring ships in your exact size. ARC comes in eight sizes, US 6 through 13.
ARC launches this fall. Waitlist members order first, in the order they joined. At launch we ship to the US, Canada, UK, EU, and Australia, with more regions following. Shipping is free everywhere we deliver.
Yes — the ARC app runs on iOS 16+ and Android 12+. Sleep, readiness, and trends live in the app; the ring itself stores up to two weeks of data offline, so you can leave your phone behind.
No. Every metric ARC measures is yours, free, forever. We sell a ring, not a rental.
All three. ARC is waterproof to 100 meters and the PVD-coated titanium shrugs off barbells and salt water. For heavy grip work, we suggest wearing it on your non-dominant hand.
Nothing. No payment, no card, no obligation — just your place in line and first access when ordering opens this fall.
● Fall 2025 — First access
Waitlist members order before anyone else, get the sizing kit free, and hear from us only when it matters. No spam — we're too busy machining titanium.
You're on the list.
Watch your inbox, friend — sizing kits and first orders open this fall.
ARC · Fall 2025