An expandable in-ear device (10) for being custom fitted in-situ into the ear canal (C) and cavum concha (V) of an individual by injection of a settable compound material (23) therein. The device (10) includes a core-form (20) with a platform section (30) and a nipple section (40) being integral to and extending from the platform proximal end (31) for engaging the canal (C). A sound bore (21) extends from the nipple proximal end (41) to the platform distal end (32) to conduct sound from the environment to inside the ear canal (C). A stretchable sheath (50) is integral to and frely extends away from the nipple proximal end (41) in an unfolded configuration of the device (10). The sheath (50) is a mirror image of the shape of the core-form (20) and has an aperture (51) for assuming a periphery (34) of the platform distal end (32). The sheath (50) folds inside-out over the core-form (20) to substantially assume the latter and to define an in-between region (22) therebetween in the folded configuration. The platform section (30) allows for the settable compound material (23) to be injected therethrough and reach the in-between region (22), thereby expanding the device (10) fitted inside the ear canal (C) by stretching the sheath (50) away from the core-form (20) to perfectly assume and occlude the ear canal (C).Linvention concerne un dispositif intra-auriculaire à volume variable (10) destiné à être adapté sur mesure in-situ dans le conduit auditif externe (C) et la conque (V) dune personne, par linjection dun matériau composé durcissable (23) dans celui-ci. Ledit dispositif (10) comprend une partie centrale (20) possédant une partie plate-forme (30) et une partie en forme de mamelon (40) faisant partie intégrante de lextrémité proximale (31) de la plate-forme et sétendant depuis celle-ci, de manière à sengager dans le conduit (C). Un orifice de transport du son (21) sétend de lextrémité terminale (41) de la partie en forme de mamelon jusquà lextrémité distale (32) de l
