Smart mask aims to measure blood oxygen through your face

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Healthy subjects with ASA health score of I or II * Subjects aged between ≥ 18 and ≤ 65 years. * Subjects who have provided informed consent and are willing to comply with the study procedures. Exclusion Criteria: * Heavy smokers or individuals exposed to high levels of carbon monoxide resulting in elevated carboxyhemoglobin levels. * Individuals with conditions that result in elevated methemoglobin levels. * Individuals with hypoxia (SpO2 \< 95% at 21% O2). * Severe claustrophobia. * Subjects known with altitude sickness. * Subjects who are obese (BMI ≥ 35 kg/m2). * Subjects with a known history of moderate to severe heart, lung, kidney or liver disease. * Subjects diagnosed with moderate to severe asthma. * Subjects with a hemoglobinopathy or history of anemia, e.g. sickle cell anemia, thalassemia, that in the investigator's opinion, would make them unsuitable for study participation. * Subjects with any other serious systemic illness. * Any injury, deformity, or abnormality at the sensor sites that, in the investigator's opinion, would interfere with the correct functioning of the test or reference devices. * Subjects with a history of fainting or vasovagal response. * Subjects with a history of sensitivity or allergy to local anesthetics or disinfectants if included in the IN study. * Subjects diagnosed with Raynaud's disease. * Subjects with unacceptable collateral circulation based on examination by the investigator. * Subjects who are pregnant, lactating or trying to become pregnant. * Subjects unable or unwilling to provide informed consent or comply with study procedures. * Subjects with any other condition that, in the investigator's opinion, would make them unsuitable for the study. * Subjects who refuse to remove nail polish from their index finger. * Volunteers not willing to remove facial make-up.