Fzone Aquarium Co2 Regulator Dc Solenoid With Bubble Counter And Check Valve DUAL Big GAUGE! 1.6 inch big dual gauge easy to read your cylinder inner and working Pressure. UPDATED SPLIT-TYPE DC SOLENOID! Newest 12 DC split-type solenoid instead AC models, more safe and stable. HIGH PRECISION STRUCTURE-This regulator is designed for the aquarium. High precision fine-tuning easy for co2 to be 1 bubble in 3 seconds. Upgraded sealing material avoid any leak. BUBBLE COUNTER AND TOOLS INCLUDED! Together with bubble counter, you can read your co2 flow rate. Bubble counter with check valve function, stop water backflow to bottle. All installing tools included, make all goes easy. CLASS 1 MANUFACTURING TECHNOLOGY! Made of hard aluminum alloy, surface spraying treated. Pressure knob and fine tuning knob with knurl. One-year Warranty?Fzone will offer a one-year warranty, round-the-clock service, and you can reach out to us at any time for any product-related concerns.