A device for automatically providing needles to a sealing apparatus for sealing a puncture in an anatomical structure, the sealing apparatus including a needle insertion lumen and a needle pusher channel having a needle pusher disposed therein. The device may include a housing coupled to the sealing apparatus and a cartridge disposed in the housing. The cartridge has a first and a second needle slot extending from a distal end of the cartridge to a proximal end of the cartridge. The first and second needle slots have first and second needles disposed, e.g., pre-loaded, therein, respectively. The cartridge is moveable, such as by a biasing element, relative to the housing between a first position in which the first needle slot is aligned with the needle insertion lumen and the needle pushing channel, and a second position in which the second needle slot is aligned with the needle insertion lumen and the needle pushing channel.