It estimates your risk of obstructive sleep apnea using the 8-item STOP-BANG framework: Snoring, Tiredness, Observed pauses, Pressure (blood pressure), BMI, Age, Neck size, and Gender. Scores of 0-2 indicate low risk, 3-4 intermediate, and 5-8 high risk — a score of 3 or more is a sensitive signal for moderate-to-severe OSA