An ink cartridge includes an ink chamber, and a movable member disposed within the ink chamber. The movable member includes a signal blocking portion, and a float portion. The ink cartridge also includes a guide, and the movable member is configured to move between a first position and a second position based at least on an amount of ink disposed within the ink chamber. Moreover, when the moveable member moves from the first position to the second position the moveable member slides along the guide.