Validation of the Smart Mask V1 System and Its Measurements of SpO2 and Pulse Rate

The goal of this clinical study is to investigate a new medical device, the Smart Mask V1 System (herein 'Smart Mask'), and particularly its measurements of blood oxygen levels (SpO2) and pulse rate (PR) in healthy adults aged 18 to 65. More specifically, the study is directed at answering the following questions: * Can the Smart Mask accurately measure SpO2 levels compared to established reference devices (reference oximeters, blood gas) throughout the range of SpO2 \~ 70 - 100%? * Can the Smart Mask accurately measure PR during the same conditions? * Does skin pigmentation impact the accuracy of Smart Mask's measurements of SpO2 and PR. The following reference devices will be used in the study: * An FDA-cleared fingertip pulse oximeter (Nellcor Portable SpO2 Patient Monitoring System, PM10N) * A laboratory-grade CO-oximeter (Radiometer ABL90 FLEX) that analyzes oxygen saturation from blood samples. Study participants will: * Wear the Smart Mask on their face and a fingertip pulse oximeter while lying down * Breathe air with gradually reduced oxygen levels inside a specialized hypoxia room while being closely. * In a second phase of the study, have a catheter inserted into a wrist artery for blood sampling to directly measure oxygen levels with the CO-oximeter.