Check the listing for details. Hydroponics CO2 Regulator Emitter System w/ Solenoid Valve Flowmeter Garden Grow. Condition: New. Listed at 39.95 USD. VIVOSUN Hydroponics CO2 Regulator Emitter System with Solenoid Valve Flowmeter for Grow Room Grow Tent Garden House Aquarium Durable Material: Long-lasting durable brass components will function for many years without rustingSpecifications: 1.58" high pressure gauge: 0-4000 PSI; Flowmeter: 0-15 SCFH; Inlet connection: cga-320Application: Perfect for enhancing the amount of available carbon dioxide and accelerating plant growth rates and yields by up to 40% in indoor hydroponics, grow rooms, grow tents and warm housesComponents: A precision regulator, flow gauge, and industrial solenoid valve, 5 meters free plastic dispensing tubing and USA standard 3-prong plug (hose tail to suit 4.2 mm hose diameter)Multiple Options: This CO2 regulator will allow you to maintain ideal CO2 levels for optimal growth