In this study, the level of oxygen within the blood will be reduced in a controlled manner by reducing the concentration of oxygen the study volunteer breathes. The accuracy of a noninvasive pulse oximeter sensor will be assessed by comparison to the oxygen saturation measurements from a laboratory blood gas analyzer.

Competent non-smoking adults

Inclusion Criteria:

• Subjects must understand and consent to be in the study.
• American Society of Anesthesiology Class 1 (Healthy subjects without any systemic disease at all).

Exclusion Criteria:

• Subjects who have any systemic disease at all.
• Subjects who do not understand the study and the risks.
• Smokers.
• Subjects who are pregnant.
• Subjects having either signs or history of peripheral ischemia.
• Others deemed ineligible by the clinical staff.