new and high quality aquarium Co2 system Easy-to-install aquarium Co2 diffuser The CO2 system is designed for low cost planted use. Colour: white-gray Material: plastic + stainless steel Package Contents: 2 * bottle cap 1 * Pressure gauge (including simple pressure relief valve) 1 * fine adjustment valve 1 * switch valve 1 * Acid suction tube (including water-absorbing ball) 1 * acid pipe (including tee) 1 * Magnet 1 * 1.6m trachea Tips to install: The bottle should be a soft drink bottle, not use pulpy, green tea, mineral water bottles, etc. The cutting valve regulation avoids by a sudden large or small, suddenly can not turn, after stopping immediately again, so as not to cause abnormal pressure to the bottle. Note: Be sure to carefully observe the direction of parts before assembly. The usual wrong handle means will cause abnormal reaction components as follows: reverse direction of the check valve and fine tuning in direct. Only the above package content, other products are not