Accuracy of ScanWatch Pulse Oximeter With Profound Hypoxia

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 has both wrist circumferences between 14 and 22cm. * 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. * The subject has piercings that may cause air leaks during the test * The subject has 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 a resting heartrate over 120, Systolic BP is over 150, diastolic BP is over 90 or room air SpO2 is less than 94%. * The subject has carboxyhemoglobin over 3% as measured by Lab blood gas analysis. * The subject has any other condition, which in the opinion of the investigators' would make them unsuitable to participate.