Inclusion Criteria:
* Participant must have the ability to understand and provide written informed consent.
* Participant is an adult between 18-50 years of age.
* Participant must be willing and able to comply with study procedures and duration.
* Participant is a non-smoker or who has not smoked within 2 days prior to the study.
* Male or female assigned at birth of any race.
Exclusion Criteria:
* Participant is considered as being morbidly obese (defined as BMI \>39.5)
* Compromised circulation (i.e., Raynaud's Syndrome), injury, open wound, or physical malformation of fingers, toes, hands, ears or forehead/skull or other sensor sites which would limit the ability to test sites needed for the study. Tattoos in the optical path which would limit the ability to test sites needed for the study. (Note: Certain malformations may still allow participants to participate if the condition is noted and would not affect the sites utilized.)
* Females who are pregnant
* Females who are trying to get pregnant (with confirmation of positive urine pregnancy test unless the participant is known to be not of child-bearing potential)
* Participants who have smoked in the last 2 days or participants who have refrained, for at least 48 hours, with COHb levels \>3% as assessed with a Masimo Radical 7 (Rainbow)
* Participants with known respiratory conditions such as: (self-reported)
* uncontrolled / severe asthma,
* flu,
* pneumonia / bronchitis,
* shortness of breath / respiratory distress,
* unresolved respiratory or lung surgery,
* emphysema, COPD, lung disease
* Recent COVID with or without hospitalization (last 2 months)
* Participants with self-reported heart or cardiovascular conditions such as: (self-reported, except for blood pressure and ECG review)
* high blood pressure: systolic \>140 mmHg or diastolic \>90 mmHg on 3 consecutive readings (reviewed during health screen)
* have had cardiovascular surgery, except successful minor surgery without clinical symptoms (i.e., PFO, PDA)
* chest pain (angina)
* heart rhythms other than a normal sinus rhythm or with respiratory sinus arrhythmia (reviewed during health screen)
* previous heart attack
* blocked artery
* unexplained shortness of breath
* congestive heart failure (CHF)
* history of stroke
* transient ischemic attack
* carotid artery disease
* myocardial ischemia
* myocardial infarction
* cardiomyopathy
* implantable active medical device such as pacemaker or automatic defibrillator
* Self-reported health conditions as identified in the Health Assessment Form
* diabetes,
* uncontrolled thyroid disease,
* kidney disease / chronic renal impairment,
* history of seizures (except childhood febrile seizures),
* epilepsy,
* history of unexplained syncope,
* recent history of frequent migraine headaches,
* recent symptomatic head injury (within the last 2 months),
* Cancer requiring chemotherapy, radiation, or current treatment.
* Participants with known clotting disorders (self-reported)
* history of bleeding disorders or personal history of prolonged bleeding from injury
* history of blood clots
* hemophilia
* current use of blood thinner: prescription or daily use of aspirin
* Sickle Cell Trait or Disease
* Participants with self-reported dermatological conditions at sensor application sites
* severe dermatitis
* hyperkeratosis
* nail fungus
* Participants with severe contact allergies to standard adhesives, latex, silicone or other materials found in pulse oximetry sensors, ECG electrodes, respiration monitor electrodes or other medical sensors (self-reported)
* Participants with severe allergies to iodine (only applicable if iodine is used)
* Participants with severe allergies to lidocaine (or similar pharmacological agents, e.g. Novocaine)
* Participants with allergies to ultrasound gel
* Failure of the Perfusion Index Ulnar/Ulnar+Radial Ratio test (Ratio \<0.4)
* Unwillingness or inability to remove nail polish, nail jewelry, or artificial nails from test digits. Bruised nail bed of test digits (Note: Certain bruising may still allow participants to participate if the condition is noted and would not affect the sites utilized.)
* Unwillingness or inability to cut/trim fingernail(s) of test digits if determined length will interfere with correct application of the sensor.
* Participant received intravascular dye within the past 48 hours (e.g. Indocyanine green, methylene blue, indiocarmine, dyes used in cardiac output monitoring)
* Surgical hardware in pathway of Device Under Test
* Other known health conditions should be considered upon disclosure in health assessment form.
* Participants with uneven skin tone at the sensor site or at the forehead
* Participants who were previously enrolled and/or included in the terminated Optimus Validation study
