An attachable needle assembly (2) for use on a medication delivery pen (4), the needle assembly (2) comprising a housing (16) that engage the medication delivery pen (4), the housing (16) enclosing a plurality of needles (34) that pierce a reservoir septum (6) of the medication delivery pen (4), a plurality of needle posts (24) each securing one of the plurality of needles (34), and a needle assembly septum (60) enclosing the plurality of needles (34). The needle assembly (2) further including a plurality of integrated peel tabs (70) each detachably connected to one of the plurality of needle posts (24), wherein in a first position of the needle assembly (2), the plurality of needles (34) is disposed in the needle assembly septum (60), and in a second position of the needle assembly (2), one of the plurality of integrated peel tabs (70) is drawn out of the housing (16) to cause a selected needle (40) of the plurality of needles (34) to pierce the needle assembly septum (60) and be exposed for medication delivery.