A-1H model of the A-1 Skyraider was a single-seat attack aircraft with three dive brakes, centerline station stressed for 3,500 lb (1,600 kg) of ordnances, 30 inches (760 mm) in diameter, combination 14/30 inch (360/760 mm) bomb ejector and low/high altitude bomb director. A-1H was a converted AD-6 aircraft and there were 713 built. A-1H has a distinction between the A-1J aircraft variant. The two said variants, A-1H and A-1J, were the final versions of the Skyraider. The H and J models were externally identical; however, the A-1J had strengthened landing gear and wings. The principal mission of the A-1H/J is the destruction of ground targets in support of ground forces. The aircraft's middle compartment can be readily equipped with passenger seats, facilities for litters or provisions for carrying heavy cargo. The USAF used the Skyraider extensively in Vietnam in the close air support role. The aircraft was especially effective in providing cover for combat rescue missions.