A drug delivery device with differentiating features is provided. The drug delivery device comprises a dose setting mechanism, a cartridge holder, and a cartridge contained within the cartridge holder. The cartridge holder is secured to the dose setting mechanism and comprises a collar or ring. The ring has the same color as other differentiation features on either the dose setting mechanism or the cartridge, or both. The color-coded ring is configured on the cartridge holder such that when the cartridge holder is assembled with the dose setting mechanism, the color-coded ring remains visible.