Pulse Oximeter Accuracy During Stable Hypoxia Plateaus

Inclusion Criteria: * The subject is male or female, aged 18 to 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: 1. The subject has a BMI above 40 2. The subject has blood pressure above 160 systolic or 95 diastolic 3. The subject has a known history of heart disease, lung disease, kidney or liver disease. 4. Diagnosis of asthma, sleep apnea, or use of CPAP. 5. Subject has diabetes. 6. Subject has a clotting disorder. 7. The subject has 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. (COHb\<3%, MetHb\<2%, ctHb\>10 g/dL). 8. The subject has any other serious systemic illness. 9. The subject has smoked in the last 12 hours. 10. Any injury, deformity, or abnormality at the sensor sites that in the opinion of the investigators would interfere with the sensors working correctly. 11. The subject has a history of fainting or vasovagal response. 12. The subject has a history of sensitivity to local anesthesia. 13. The subject has a diagnosis of Raynaud's disease. 14. The subject has unacceptable collateral circulation based on exam by the investigator (Allen's test). 15. The subject is pregnant, lactating or trying to get pregnant. 16. Subjects who have uneven skin tones at the forehead or the sensor site. 17. The subject is unable or unwilling to provide informed consent or is unable or unwilling to comply with study procedures. 18. The subject has any other condition, which in the opinion of the investigators would make them unsuitable for the study.