Scale: 1:38.4. A full hull model of the 'Sun XXI' (1959), a tug. Model is decked and equipped. The hull is inscribed with ‘Sun XXI’ on port and starboard bows, ‘Sun XXI London’ on the stern. Built as a radio controlled model it is complete with crew working on board.

Many models of this type were made due to commercially available drawings. This model gained many awards: 1972 West london MPB Club Prototype Trophy; 1973 Model engineer Championship Cup and MPB Association Prototype Cup; and 1974 Duke of Edinburgh Challenge Trophy. The model was also selected as part of a team representing Britain in a European championship of 1975.

Features include electric lights and engine room skylights operated by a lever. All doors close and lock and a towline can be thrown from the stern. The lifeboat can be launched manually and the fire monitor throws a jet of water 5-6 feet. The pump is also operational. It has motor steering, a foghorn, fire monitor, radio and tow line which can be manually operated. The model is powered by a 6000 RPM electric motor through a 3:1 gearbox driving a 2 ½-inch screw.