The SDV MK VIII is a free-flooding wet submersible designed for undersea special operations including direct action, hydrographic reconnaissance, and insertion and extraction of SEALs. It carries a pilot, co-pilot, and combat swimmer team with their equipment to and from maritime mission objectives on land or at sea, and the pilot and co-pilot are often part of the fighting team. It has compressed air to extend the range of a swimmer's own air tank or rebreather, and it is lithium-ion battery powered and equipped with propulsion, navigation, communication, and life-support equipment. It can deliver several fully equipped SEALs to a mission area, be parked or loiter there, retrieve the SEALs, and return home. SDVs are generally launched from a Dry Deck Shelter on the back of a submarine or from amphibious carriers equipped to launch and recover them, and it can also be airdropped unmanned into an operational area from a C-130 Hercules.