Coded drug reservoir connection element with hinged flange

A system comprising:

• a drug delivery device comprising:
• a reservoir holder, and
• a reservoir contained within the reservoir holder;
• and
• a locking mechanism comprising:
• a main body configured to be coupled to the reservoir, the main body comprising a proximal end and a distal end and defining an aperture at the proximal end, and
• at least one flange provided at the proximal end of the main body, the flange comprising a hinge and being configured to fold on the hinge, such that at least a portion of the flange is folded on the hinge into the aperture toward an inner surface of the main body and abuts against a neck of the reservoir and retains the locking mechanism on the reservoir when the locking mechanism is mounted with its aperture on the reservoir, wherein the neck of the reservoir projects distally from a shoulder part of the reservoir,
• wherein the flange is pointing in a proximal direction when the flange is unfolded, and wherein the flange is pointing in a distal direction when the flange is folded,
• wherein the locking mechanism is retained to the reservoir and to the reservoir holder.