In everyday medical treatment, therapeutic processes are being transferred to patients ever more frequently. An easy-to-use method for self-injecting liquid medication is therefore increasingly gaining in significance. The Duo Pen takes this aspect into consideration by significantly simplifying the injection process, reducing it to the steps “initialisation – dosage selection – injection”. And thanks to a mechanically defined handling system, the risk of error in usage is minimised, thus also meeting requirements for increased patient safety.