To determine accuracy specifications of the Pulse oximeter.

Inclusion Criteria:

1. Male or female subjects between the ages of 18 to 50 years (inclusive).
2. Must undergo a physical examination by a licensed physician, advanced practice nurse or physician assistant, including a 12 lead ECG, a medical history, and a blood test checking complete blood count and screening for sickle cell trait or disease
3. All female volunteers must have a negative urine pregnancy test prior to participation.

Exclusion Criteria:

1. Pregnancy or lactating women
2. Unexplained syncopal episodes
3. Hypertension (defined as a systolic pressure of >145 mmHg or a diastolic pressure >90 mm Hg on three consecutive readings)
4. Premature ventricular contractions (PVC's) that are symptomatic or occur at a rate of more than 5/minute
5. History of seizures (except childhood febrile seizures) or epilepsy
6. Routine use of tranquilizers and/or excessive anxiety
7. History of frequent headaches or migraines
8. History of stroke
9. Previous injury or trauma to fingers or hands that may change blood flow or vascular supply and affect our ability to test multiple sensors
10. History of "altitude sickness" defined as headaches, malaise or dizziness when in the mountains or in an aircraft at altitude significantly above sea level for a prolonged period of time (> 1 hour)
11. History of significant respiratory disease, such as severe asthma, emphysema, etc.
12. Sickle cell disease or trait.
13. The use of medications, pre-existing medical conditions, treatment for a medical condition or any other reason deemed relevant by the clinician conducting the study.
14. Abnormal ECG finding
15. Prior or known allergies to lidocaine (or similar pharmacologic agents, e.g., Novocain)
16. Prior or known allergies to heparin.
17. History of transient ischemic attacks or carotid artery disease
18. History of myocardial ischemia, angina, myocardial infarction, congestive heart failure or cardiomyopathy
19. History of chronic renal impairment
20. History of recent arterial cannulation (less than 1 month prior to study)
21. History of complications from previous arterial cannulation
22. Current use of blood thinners

Healthy Subjects