Main Inclusion Criteria:

1. 50-80 years old.
2. Ability and willingness to sign and understand an informed consent form.
3. The participant has a palpable radial pulse in both wrists.
4. The participant is willing and able to be fitted with the investigational devices, A-line, and reference cuff, and is willing and able to undergo all study procedures, including 1 hour of recording with the investigational devices and A-line.
5. Participant has good signal quality with the CS Pillow at both wrists.
6. Participant has good PPG signals in both thumbs.
7. Participant has good ECG signals using the Watch.

Main Exclusion Criteria:

1. Participant who are currently enrolled in another clinical investigation in which the intervention might compromise the safety of the participant or interfere with the data collected.
2. Participant who has previously participated in a BP study conducted by CardiacSense.
3. Participant whose body habitus precludes them from wearing the investigational devices.
4. Female participants who self-reported as pregnant based on a urine pregnancy test, or who are self-reported as trying to get pregnant or who are breastfeeding.
5. Participant whose BMI is greater than 35.
6. Participant with a documented medical history of cardiac arrhythmia or if arrhythmia was detected during the screening.
7. Participant with diagnosed diabetes mellitus.
8. Participant with implanted cardiac defibrillators or pacemakers, Ventricular Assist Device (VAD) or other mechanical circulatory support devices, whether intracorporal or extracorporeal.
9. Participant with stage 4 or stage 5 end-stage renal disease, or participants with arteriovenous shunts.
10. Participant with pheochromocytoma or primary hyperaldosteronism.
11. Participant with diagnosed heart failure with New York Heart Association (NYHA) class III/IV, or participants with a history of stroke.
12. Participant with a known clotting disorders or currently taking a prescription anticoagulants (daily aspirin use is permitted).
13. Participant with an infection requiring antibiotics.
14. Participant with autonomic dysfunction (such as orthostatic hypotension or neuropathy).
15. Participant with peripheral artery disease
16. Participants with compromised circulation, including Raynaud's syndrome.
17. Participant has a fracture, severe trauma, or anatomical deformity involving the wrist or fingers intended for placement of the investigational devices, which could interfere with proper fitting or function of the devices.
18. Participant with moderate to severe valvulopathies.
19. Participant with primary vasculitis.
20. Participant with tremors or otherwise unable to remain still for 1 hour.
21. Participants with changes to their antihypertensive medication regimen, including initiation, discontinuation, or dose modification, within 30 days prior to enrollment.
22. The left to right arm lateral difference of the average systolic blood pressure values is more than 15 mmHg or the lateral difference of the average diastolic blood pressure values is more than 10 mmHg.
23. Participant belongs to a recruitment category that has already been filled, including BMI category, height category, age group, sex, skin tone category, or blood pressure classification group.
24. Participant with contact allergy to ultrasound gel.
25. Participant with prior or known allergies to lidocaine (or similar pharmacological agents, e.g. Novocaine).
26. Participant with severe contact allergies to standard adhesives, latex or other materials found in pulse oximetry sensors, ECG electrodes, respiration monitor electrodes or other medical sensors (self-reported).
27. Participant with other known health conditions, that might put the participant at risk or might jeopardize the quality of the data collected.
28. Participant that fails the modified Allen's test (Perfusion Index Ulnar/Ulnar+Radial Ratio test) (Ratio < 0.4).