A cartridge assembly (14, 300, 700, 800, 900) configured to be connected to a dose setting and delivery mechanism (12, 302, 702, 802, 902), the cartridge assembly (14, 300, 700, 800, 900) comprising: a cylindrical body for holding a medicament reservoir, where the cylindrical body has a proximal end portion having an outer surface and an inner surface; a fastener (316, 316a, 416, 416a) on either the outer surface or the inner surface of the proximal end portion, the fastener (316, 316a, 416, 416a) being configured to attach the cartridge assembly (14, 300, 700, 800, 900) to the dose setting and delivery mechanism (12, 302, 702, 802, 902); and at least one coding feature (318, 318a, 418, 418a, 610a-c, 620a-c, 718, 918) that is separate from the fastener (316, 316a, 416, 416a), the coding feature (318, 318a, 418, 418a, 610a-c, 620a-c, 718, 918) being coded to engage a corresponding coding feature (330, 330a, 430, 430a, 510a,-c, 512a-c, 612a-c, 622a-c, 730, 931) on the dose setting and delivery mechanism (12, 302, 702, 802, 902), thereby allowing the cartridge assembly (14, 300, 700, 800, 900) to operably connect to the dose setting and delivery mechanism (12, 302, 702, 802, 902), where the coding feature (318, 318a, 418, 418a, 718, 918) is formed as stop feature and where the corresponding coding feature (330, 330a, 430, 430a, 510a,-c, 512a-c, 612a-c, 622a-c, 730, 931) is formed as counter stop feature, the stop feature and the counter stop feature being suitable to make contact thereby blocking travel in the connection process and allowing cartridge assembly (14, 300, 700, 800, 900) to operably connect to the dose setting and delivery mechanism (12, 302, 702, 802, 902), characterized in that the proximal outer surface of the cylindrical body is positioned between a shoulder (306, 809) and a proximal axial end and the fastener (316, 316a, 416, 416a) is located on the proximal outer surface and where the coding feature of the cartridge assembly (14, 300, 700, 800, 900) is a pin on the proximal outer surface, the pin abuting a proximal facing surface of the shoulder (306, 809). a cylindrical body for holding a medicament reservoir, where the cylindrical body has a proximal end portion having an outer surface and an inner surface; a fastener (316, 316a, 416, 416a) on either the outer surface or the inner surface of the proximal end portion, the fastener (316, 316a, 416, 416a) being configured to attach the cartridge assembly (14, 300, 700, 800, 900) to the dose setting and delivery mechanism (12, 302, 702, 802, 902); and at least one coding feature (318, 318a, 418, 418a, 610a-c, 620a-c, 718, 918) that is separate from the fastener (316, 316a, 416, 416a), the coding feature (318, 318a, 418, 418a, 610a-c, 620a-c, 718, 918) being coded to engage a corresponding coding feature (330, 330a, 430, 430a, 510a,-c, 512a-c, 612a-c, 622a-c, 730, 931) on the dose setting and delivery mechanism (12, 302, 702, 802, 902), thereby allowing the cartridge assembly (14, 300, 700, 800, 900) to operably connect to the dose setting and delivery mechanism (12, 302, 702, 802, 902), where the coding feature (318, 318a, 418, 418a, 718, 918) is formed as stop feature and where the corresponding coding feature (330, 330a, 430, 430a, 510a,-c, 512a-c, 612a-c, 622a-c, 730, 931) is formed as counter stop feature, the stop feature and the counter stop feature being suitable to make contact thereby blocking travel in the connection process and allowing cartridge assembly (14, 300, 700, 800, 900) to operably connect to the dose setting and delivery mechanism (12, 302, 702, 802, 902), characterized in that the proximal outer surface of the cylindrical body is positioned between a shoulder (306, 809) and a proximal axial end and the fastener (316, 316a, 416, 416a) is located on the proximal outer surface and where the coding feature of the cartridge assembly (14, 300, 700, 800, 900) is a pin on the proximal outer surface, the pin abuting a proximal facing surface of the shoulder (306, 809).