Check the listing for details. US Seller DC CO2 Mini Regulator Aquarium Display with Bubble Counter Check Valve. Condition: New. Listed at 76.19 USD. Features: Dual stage decompression,pressure adjustable. This aquarium co2 regulator is the triple stage design, very stable output pressure and CO2 flowrate, cylinder inner pressure reduced, flowrate will not change. Working pressure can be adjusted from 0-60 psi. 12V DC solenoid with precision needle valve. This co2 regulator use 12V DC solenoid valve repalced AC solenoid valve, safer and more stable, lower power, no noise. Automatic turning on/off CO2 output with timer. Aquarium specific needle valve, High precision fine-tuning easy for co2 to be 1 bubble in 3 seconds. Bubble counter and tools included. Together with bubble counter, you can read your co2 flow rate directly via the bubble counter. Bubble counter with check valve function, stop water backflow to bottle. All installing tools included, easy to install and use. Class 1 manufacturing technology. The co2 regulator is made of hard aluminum alloy, surface spraying treated. Pressure knob and fine tuning are very easy to adjust. Mini size for almost all tanks. The regulator compatible with Painball tank, all size CGA320 threaded cylinder and 5/8'' UNF threaded disposable co2 cartridge.(Most 80-90g cartridges are 5/8'' UNF thread. Fluval 45g threaded 3/8'', NOT suitable)