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Signal

Signal Ring

The first ring claiming calibration-free continuous blood pressure. The most interesting device in this list — and the one to be most sceptical about until it's validated.

Year one
$399
one-off
Hardware
$399
$399 pre-order
Subscription
None
not required
Battery
Not published

Signal is pitching something nobody has convincingly delivered: continuous, cuffless blood pressure from a ring, with no calibration against a cuff. It uses pulse-wave analysis via a high-resolution optical sensor. If it works, it's a genuine breakthrough — blood pressure is the single highest-value number in cardiovascular health, and once-a-day cuff readings miss almost everything that matters, including nocturnal non-dipping. The reason to hold judgement is history: cuffless BP has repeatedly failed independent validation, and 'no calibration' makes the claim harder, not easier. There is no published validation against a reference standard yet.

Is the measurement validated?

None published. No peer-reviewed comparison against a reference cuff, and no clearance stated. Cuffless blood pressure has a long track record of failing ISO 81060-2 / AAMI validation, and calibration-free is the hardest version of the problem. Treat any reading as directional until independent validation exists — do not make medication decisions on it.

What it measures · 4

  • Blood pressure — systolic
  • Blood pressure — diastolic
  • Heart rate
  • Heart-rate variability (HRV/SDNN)

Does it reach your record?

Unknown

Not yet known — unreleased. No Whatstack connector until the API is public.

Explore your health record →

Best for

Early adopters tracking blood-pressure trends who already own a validated cuff for ground truth.

Watch out

Unreleased, unvalidated, pre-order. If you need real blood-pressure numbers today, buy a validated upper-arm cuff for a fifth of the price.

Manufacturer site

Price checked 2026-08-09 and quoted at MSRP — hardware pricing moves. Consumer devices estimate rather than diagnose; discuss anything clinical with your doctor.

within Blood pressure & heart