During the Second World War and the Korean War years the U.S. armed forces, including the USAAC / USAF, the Navy and the Marine Corps, used this type of crane for performing maintenance on their aircraft based in theatre. Having no motors, these cranes have been manually operated and employed to handle bulky items like aircraft engines and propellers.
This 1:72 scale model kit is from F4Models (cat. # 7029). It is entirely photoetched metal. To complete the kit, a modeller will need thin wire or thread to imitate the crane's rigging.
A photographs showing a USMC crane in action in Korea: link.