An attachable needle assembly (2) used on a medication delivery pen (4), the needle assembly (2) comprising a communication needle (10) configured to pierce a reservoir septum of the medication delivery pen (4), a spike housing (8) surrounding the communication needle (10) and configured to engage the medication delivery pen (4), a selector ring (16), including a selector opening (18), enclosing a septum (22, 30) of the needle assembly (2) defining a septum chamber (28, 29) that is in fluid communication with the communication needle (10), a plurality of needles (34) disposed in the septum (22, 30) of the needle assembly (2), and a peel tab (60) enclosing each of the plurality of needles (34), wherein the selector opening (18) is aligned with a selected peel tab (60) corresponding to a selected needle (40), the selected peel tab (60) is drawn out of the selector ring (16) and moves the selected needle (40) from a first position to a second position, and the selected needle (40) enters into fluid communication with the communication needle (10) in the second position.
