The invention relates to an injection device for delivering a medication comprising:a cartridge module； a delivery mechanism, the actuation thereof causing thedelivery of the injection agent； a dosing adjustment mechanism for adjustingthe dosage at which the injection agent is delivered when the delivery mechanismis actuated, wherein the dosage adjustment mechanism comprises: a housing part(11) in which at least a part of the delivery mechanism is received, an indicatorsleeve (13) that can be rotated in said housing, and an insertion sleeve (15) thatcan be inserted into the housing part (11), wherein the insertion sleeve (15)comprises embossed and at least in some regions transparent or translucent surfacesegments (20) on the outer surface thereof, and the housing part (11) has an openrecess (25) at the distal edge (24) for the rotatably fixed reception of the insertionsleeve (15) from the open side of the recess (25).
