The invention concerns a simplified, economical and sound-absorbing method of securing a unit taking the form of a valve, for example. In order to secure the unit (1) it comprises a housing (4) with a first section (8) having a first peripheral outer surface (7) and at least one second section (9) with at least a second peripheral outer surface (6). A first sealing ring (25) can be placed on the first outer surface (7), and the first section (8) and first sealing ring (25) can be introduced into a recess (10) in an embedded wall (20). A second sealing ring (26) can be placed on the second outer surface (6) of the second section (9), and the second section (9) and second sealing ring (26) can likewise be introduced into the recess (10) such that the unit (1) is mounted in the recess (10) by means of the two sealing rings (25, 26), without the first and second outer surfaces (6, 7) of the unit (1) abutting inner surfaces (11, 12) of the recess (10). The embedded wall (20) comprises a sleeve-like attachment (36) into which the recess (10) extends and which is divided into a plurality of flexible annular snap-action elements (40) for holding the unit (1), into which elements the second sealing ring (26) can snap when the unit (1) is introduced into the recess (10). The unit according to the invention and the snap-action device therefor are intended in particular for valves for the metered introduction of volatilized fuel into an internal combustion engine intake duct.