A simple small bore oscillating single cylinder and vertical boiler that you assemble from machined brass and copper components. Requires the use of solder and a propane torch (not recommended for children). Designed for use with Sterno fuel. Boiler - Length: 5 inches, Width: 3 inches, Height: 7-1/2 inches; Mainframe - Bore: 9/32 inches, Stroke: 1/2 inch. Powers boat models with hull lengths less than 24 inches. Midwest no. 980.