Check the listing for details. Aquarium Plants CO2 Regulator Precise Needle Valves Adjustable Bubble Counter. Condition: New, Made in China. Listed at 5.58 USD. Co2 regulator for applies nut lock design can effectively lock the CO2 tube, to prevent the accidents caused by loose. Aquarium Valve-Regulator Diffuser Single-Head/Dual-Head CO2 only, other accessories in the picture is not included!