ITEM NAME:2pcs Aquarium Fish Tank Plant Aluminium CO2 Bubble Counter with Check Valve Description: Aluminium Aquarium Inline CO2 Bubble Counter with build in check valve. When the regulator is open, you will be able to calculate your CO2 injection rate by counting how many bubbles pass through the counter per minute, with the piece of mind that your equipment is protected in the event of water siphoning back towards your equipment. A must have for any tank with CO2 injection, a bubble counter allows the user to estimate the CO2 injection rate by counting how many bubbles pass through the counter per minute. A check valve prevents water from your aquarium from siphoning back into fragile and expensive CO2 equipment such as regulators and solenoids. Easy to read and easy to maintain. Designed in a typical bubble counter shape, this clear aluminium bubble counter is a tried and tested design; perfect to get an accurate bubble count without the need of bulky and expensive equipment. To use, simply unscrew one end and fill the bubble counter with water, or if you prefer a bright coloured solution to make it easier to read. Specification: Material: Aluminum Alloy + Glass Length: Approx. 8cm/3.15inch Type: Single Head Bubble Counter + Dual Head Bubble Counter Quantity: 2pcs Package Includes: 2 Pieces CO2 Bubble Counters Note: It is recommended to use 2-3 CO2 bubbles for 1 second. Since the size above is measured by hand, the size of the actual item could be slightly different from the the size above. Due to the lighting effects, monitor settings,etc.There could be some slight difference in the color tone of the pictures and the actual item. SKU: DMO0015370019401903.Aluminium Aquarium Inline CO2 Bubble Counter with build in check valve. A must have for any tank with CO2 injection, a bubble counter allows the user to estimate the CO2 injection rate by counting how many bubbles pass through the counter per minute.