The mine consisted of a large fuel cylinder 53 cm / 21 inches high and 30 cm / 11¾ inches with a capacity of 29.5 liter / 7.7 gallons containing a black viscid liquid, a mix of light, medium, and heavy oils. A second smaller cylinder 67 mm / 2-5/8 inches in diameter and 25 cm / 10 inches high is mounted on top of the fuel cylinder; it contains the propellent powder, which was normally either black powder or a mixture of nitrocellulose and diethylene glycol dinitrate. A flame tube is fixed centrally on top of the fuel cylinder, it is a 50 mm / 2 inch diameter pipe that rises from the center of the tank and curves to extend horizontally approximately 50 cm / 20 inches. When the mine is buried, normally only the flame tube extends from the ground.
When the mine is triggered, a squib charge detonates the propellent, which forces the fuel from the main cylinder and out of the flame tube. A second squib ignites the fuel as it passes out of the end of the flame tube. The flame projected is 4.5 m / 5 yards wide and 2.7 m / 3 yards high with a range of about 27 m / 30 yards, and lasts about 1.5 seconds.