World War II. They were modified service shoes, with an extended, rough-out or, more commonly, a smooth leather high-top cuff added. The cuff was closed using two buckles, allowing the boots to replace the existing service shoes and leggings worn by most soldiers with a more convenient and practical solution. The boots, and the service shoes from which they were made, had a one piece sole and heel, made from molded synthetic or reclaimed rubber. These "double buckle" boots were worn through the Korean War as a substitute for the Boots, Russet, Leather Lace Up introduced in 1948. The first type of Combat Boots, or Combat Tropical boots were based on the "buckle boot" design and worn during the early parts of the Vietnam War. In 1957, the US Army switched to shined black combat boots, although the transition to black boots was not completed until late in the Vietnam War, which also saw the introduction of the jungle boot. Both of these boots had a direct molded sole. The jungle boot had a black leather lower and an olive drab canvas (later nylon) upper. Black boots continued to be worn following Vietnam, with the M81 BDU, although non-shine boots were considered by the Army. As the BDU was replaced with the MCCUU, Army Combat Uniform, and Airman Battle Uniform the services moved to more practical, non-shine footwear. The only current military service mandating shined black combat boots are the United States Naval Sea Cadet Corps, the Auxiliary Cadet Detachment of the Naval forces, and the Civil Air Patrol, the Auxiliary of the U.S. Air Force, in conjunction with the BDU utility uniform. As the United States Marine Corps made the transition from its utility uniform to the MCCUU, they discarded shined black combat boots, and switched to more functional tan rough-out (non-shine) combat boots, with either hot weather or temperate weather versions. The standard-issue boot is the Bates Waterproof USMC combat boot. Commercial versions of this boot are authorized without limitation other than they must be at least eight inches in height and bear the Eagle, Globe, and Anchor on the outer heel of each boot. Beginning on October 1, 2016, Marine Corps personnel were authorized to wear various Marine Corps Combat Boot models from Danner, Belleville, McRae and Bates, and Rugged all-terrain boots from Danner. The United States Army followed suit in 2002 with the introduction of the