Abstract: An adjustment mechanism variably adjusts the cross-section of a compressor inlet. The adjustment mechanism comprises a plurality of rotatable orifice elements and a transmission ring. Each orifice element has a plate body, a coupling element and a bearing pin. The transmission ring is mechanically coupled to the orifice elements via the coupling elements. One of the orifice elements is configured as a drive orifice element. The bearing pin of the drive orifice element is configured as an elongated bearing pin. The elongated bearing pin is configured longer than the bearing pins of the other orifice elements. Furthermore, the elongated bearing pin is adapted to be coupled to an actuation system such that when the drive orifice element is moved by the actuation system, movement is transmitted from the drive orifice element via the transmission ring to the other orifice elements.