An earpiece for a hearing device, the earpiece comprising an ear canal part to be introduced into the ear canal of a user, the ear canal part comprising: an earpiece housing comprising a first end configured to be positioned medially inside the ear canal of the user, and a second end configured to be positioned laterally to the ear canal of the user, where the earpiece housing comprises a side wall extending from the first end to the second end, where the side wall at least partly defines a first volume inside the earpiece housing； a primary sensor where the primary sensor is positioned inside the first volume of the earpiece housing； where the side wall of the earpiece housing comprises a first pass-through area, and wherein the primary sensor is configured to measure a physiological parameter through the first pass-through area.
