Provided is a cassette unit suitable for use with an auto-injector having a drive unit. The cassette unit comprises a cassette unit housing defining a cassette unit housing cavity arranged for receipt of a syringe; a needle projection aperture; a needle cover defining a needle sheath for sheathing of a needle tip of the syringe; a removable cap that in a capping position fits over and thereby, acts such as to close off, the needle projection aperture, the removable cap defining a cap interior; provided to the removable cap, a cap insert; and provided to the cap insert, a connector defining one or more needle cover gripping elements for gripping the needle cover and the connector defines a central hub and the one or more needle gripper elements attach to the central hub and in spaced arrangement relative to each other, wherein the connector locates within the removable cap such that the central hub of the connector is in spaced relationship with a forward end wall or surface of the cap interior and the needle cover gripping elements project away from the forward end cap wall or surface of the cap interior and towards the open end of the cap, and wherein the removable cap is shaped to allow for limited axial travel of the cap insert there within.