Purpose: Investigate the safe wearability and basic functionality - epidermal melanin concentration and blood oxygen estimation - of our developed device: Melanin-Adjusted Blood Oxygen Sensor (MABOS)

Participants: Healthy adults 18-65 years of age

Procedures (methods): The investigators plan to enroll 12 healthy adult participants for the study. The investigators aim to enroll 4 participants with skin tones associated with those of African descent (Group A), 4 of East Asian descent (Group B), and 4 of European descent (Group C). Additionally, the investigators aim to ensure half of group is male, and the other half female. For the duration of the study, two wearable devices will be placed on the participant: a Nonin PureSat pulse oximeter on a forefinger, and the novel wearable pulse oximeter - MABOS - on the other forefinger. Prior to testing, an Ocean HR2 XR Spectrometer will be used to assess the absorbance of three wavelengths of light - 410, 660, 940 nm - on each patient's inner wrist. Following this, the two devices will be placed on the patient, set up, and calibrated for 10 minutes. During the calibration period, MABOS will be used to measure the same three wavelengths of light utilized by the Ocean HR2 XR Spectrometer (410, 660, and 940 nm). After the calibration period, all participants will be asked to perform the following procedure 5 times as part of the testing period: a deep inhalation lasting no longer than 10 seconds, followed by a slow exhalation lasting no longer than 30 seconds. Between each trial, a five-minute break will be required. For the entire testing period, all two devices will be continuously acquiring data. After this testing period, all two devices will continue taking measurements until 90 minutes have elapsed. Skin integrity will be examined before spectrometer use, after spectrometer use, after the calibration period, every 30 minutes after the start of the testing period, and after the testing period. During the study, if the participants report any uncomfortable feeling and/or pain or if a change to the skin at the site of device placement occurs, the measurements will be discontinued, and all the devices placed on the participants will be removed. Questionnaires will be provided after the study period and during follow-up visits approximately 48 hours and 96 hours post the device testing visit for a proof-of-concept evaluation of the safe wearability.

Inclusion Criteria:

• Male and females, with age between 18-65
• Health individuals (defined as: not known to suffer any significant illnesses relevant to the proposed study, cited from The Textbook of Pharmaceutical Medicine)
• The investigators aim to enroll 4 participants with skin tones associated with those of African descent, 4 of East Asian Descent, and 4 of European Descent. Additionally, the investigators aim to ensure half of the group is male, the other half female.

Exclusion Criteria:

• Pregnant or lactating
• History of active (clinically significant) skin disorders that make skin vulnerable to contact conventional electronic devices.
• History of allergic response to silicones or adhesives (such as 3M Tegaderm)
• Broken, damaged, or irritated skin or rashes near the sensor application sites
• Subjects who are physically or cognitively unable to perform activities of daily living, assessed at the discretion of the investigator to ensure safe completion of study tasks.
• Inability to perform the breathing tests - deep inhalation for 10 seconds, followed by a slow exhalation no longer than 30 seconds.
• Presence of tattoos on fingers, hands, or forearms.

Individuals of African, East Asian, and European descent; equal proportions of male and female individuals from each group.