An insulin infusion set (30) for use with an inserter (40) is disclosed. The infusion set (30) includes an extension set (50). The extension set (50) includes a housing (70), a base (90) and a latching device (82). The base (90) houses a base septum (120) and an infusion cannula (42). The latching device (82) releasably attaches the housing (70) to the base. When the housing (70) is attached to the base (90), a part of the housing (70) extends into and opens the base septum (120).
