A housing and a cap for a drug delivery device is provided, comprising a metal element (150, 132) and a plastic element (131, 133) which together form a functional unit. The metal element (150, 132) and the plastic element (131, 133) are fixedly coupled to each other, and the metal element (150, 132) provides an outer surface of the assembly which is configured to be handled by a user. Furthermore, a drug delivery device (1) is provided comprising the housing or cap, and having a weight less than 30 g. Furthermore, a method of producing a housing or a cap is provided, wherein the metal element (150, 132) is slid over the plastic element (131, 133) in a longitudinal direction.
