In a sleeve element for the axially fixing at least one bearing of a rotatable shaft, in particular a shaft of an exhaust gas turbocharger, which sleeve element has at least one through-opening in its circumferential surface, the at least one through-opening has a substantially conical shape in the radial direction of the sleeve element at least in a section thereof, and also in a turbocharger for an internal combustion engine, which comprises a speed detection device and a sleeve element for axially fixing at least one bearing of a shaft of the turbocharger, wherein the sleeve element has at least one opening through which the speed detection device extends and which has a substantially conical shape in the radial direction of the sleeve element at least in a section thereof.