A drug delivery device comprising: a housing , a longitudinal axis (l) a cap attachable onto the housing , and extending along the longitudinal axis (l) wherein the cap comprises one or more snap features to attach the cap onto the housing and one or more orientation features to define the orientation of the cap relative to the housing when attached to the housing , wherein the rigidity of the cap varies along the longitudinal direction, wherein at least one of the one or more orientation features is located at a rigid part of the cap and at least one of the one or more snap features is located at a less rigid part of the cap , wherein the cap comprises an open end and a closed end , wherein the cap is more rigid at its closed than at its open end, such that the cap can be elastically deformed more easily at its open end than at its closed end, and wherein at least one of the one or more snap features is located near the open end of the cap and at least one of the one or more orientation features is displaced from this snap feature in a direction towards the closed end of the cap and wherein the snap feature located at the less rigid part of the cap and the orientation feature located at the rigid part of the cap have an offset along the longitudinal axis (l), characterized in that the housing comprises a cartridge holder configured to receive a cartridge containing a drug and wherein the cap can be attached such that it covers at least a part of the cartridge holder , and the cap comprises at least one protrusion at its open end , wherein at least one of the one or more snap features is located at the protrusion . a housing , a longitudinal axis (l) a cap attachable onto the housing , and extending along the longitudinal axis (l) wherein the cap comprises one or more snap features to attach the cap onto the housing and one or more orientation features to define the orientation of the cap relative to the housing when attached to the housing , wherein the rigidity of the cap varies along the longitudinal direction, wherein at least one of the one or more orientation features is located at a rigid part of the cap and at least one of the one or more snap features is located at a less rigid part of the cap , wherein the cap comprises an open end and a closed end , wherein the cap is more rigid at its closed than at its open end, such that the cap can be elastically deformed more easily at its open end than at its closed end, and wherein at least one of the one or more snap features is located near the open end of the cap and at least one of the one or more orientation features is displaced from this snap feature in a direction towards the closed end of the cap and wherein the snap feature located at the less rigid part of the cap and the orientation feature located at the rigid part of the cap have an offset along the longitudinal axis (l), characterized in that the housing comprises a cartridge holder configured to receive a cartridge containing a drug and wherein the cap can be attached such that it covers at least a part of the cartridge holder , and the cap comprises at least one protrusion at its open end , wherein at least one of the one or more snap features is located at the protrusion . <EOS>