Double burner alcohol stove. Each vaporizer tube has a thick brass brush, which can be seen taken out from one burner in the backside picture. These brushes should be cleaned regularely according to this instruction sheet. The lid of the tank has a clever feature with a little cup deep in the tank (as seen on the third picture). This cup has a spring loaded valve, and shall be used to carry a well proportioned dose of alcohol for each burners preheating need. -Lift it up from the tank, and press the valve against each preheating cup to portion the alcohol that came out when lifting it from the tank.