The aim of this study is to test the accuracy of EmbracePlus computed SpO2 during mild, moderate and severe hypoxia (a lower-than-normal concentration of oxygen in arterial blood); ie, a range of arterial HbO2 saturations from 100 to down to 70%. This is done by comparing the reading of the the subject device during brief, steady state hypoxia with a gold-standard measurement of blood oxyhemoglobin (hemoglobin carrying oxygen) saturation, that is arterial blood sample processed in a laboratory.

Inclusion Criteria:

• The subject is male or female, aged ≥18 and <50.
• The subject is in good general health with no evidence of any medical problems.
• The subject is fluent in both written and spoken English.
• The subject has provided informed consent and is willing to comply with the study procedures.

Exclusion Criteria:

• The subject is obese (BMI>30).
• The subject has a known history of heart disease, lung disease, kidney or liver disease.
• Diagnosis of asthma, sleep apnea, or use of CPAP.
• Subject has diabetes.
• Subject has a clotting disorder.
• The subject a hemoglobinopathy or history of anemia, per subject report or the first blood sample, that in the opinion of the investigator, would make them unsuitable for study participation.
• The subject has any other serious systemic illness.
• The subject is a current smoker.
• Any injury, deformity, or abnormality at the sensor sites that in the opinion of the investigators' would interfere with the sensors working correctly.
• The subject has a history of fainting or vasovagal response.
• The subject has a history of sensitivity to local anesthesia.
• The subject has a diagnosis of Raynaud's disease.
• The subject has unacceptable collateral circulation based on exam by the investigator (Allen's test).
• The subject is pregnant, lactating or trying to get pregnant.
• The subject is unable or unwilling to provide informed consent, or is unable or unwilling to comply with study procedures.
• The subject has any other condition, which in the opinion of the investigators' would make them unsuitable for the study.