The headset comprises left and right elongate ear pieces having respective first ends to receive ear tips and respective, interconnected second ends. Each ear piece includes a one-piece elongate body made of flexible and resilient material and curved outwardly to skirt round the user's head when the ear tips are applied to a user's ears. The elongate body is formed with a first length of smaller cross section and therefore of greater flexibility proximate the second end of the corresponding ear piece and with a second length of lower flexibility situated between that first length and the corresponding ear tip. Bending of the elongate bodies when the ear pieces are spread apart is therefore concentrated in the first lengths and pressure applied to the user's ears by the ear tips is mainly produced by the bent first lengths and transmitted to the ear tips through the second lengths of lower flexibility. The elongate ear pieces have respective second end sections assembled laterally adjacent to each other, and a threaded sleeve is mounted on these laterally adjacent second end sections and is rotated and displaced longitudinally to adjust the level of pressure applied to the user's ears by the ear tips.