A device for filling a reservoir. The device includes a cover portion comprising a septum window, and a bottom portion, the bottom portion configured to attach to a disposable housing assembly comprising the reservoir, wherein the cover portion and the bottom portion are rotatably attached in a locked configuration and wherein in a locked configuration, a septum is obscured through the septum window, wherein when the cover portion and the bottom portion are placed in an unlocked configuration, the cover portion rotates with respect to the bottom portion and the septum is visible through the septum window.