Description:<br /><br /> Aquarium Fish Tank CO2 Bubble Counter Air Check Valve Checker <br /><br /> Usage:<br /><br /> 1. Inject 3\/4 water into the bubble counter<br /><br /> 2. Connect air check with tube<br /><br /> 3. Connect CO2 system and CO2 diffuser<br /><br /> 4. Prepare a clock, count the bubble, about 1 bubble per second <br /><br /> <br /> Specification:<br /><br /> Material: Glass<br /><br /> Bubble Counter Length: 12cm\/4.7&amp;quot;<br /><br /> Check Valve Length: 8cm\/3.15&amp;quot;<br /><br /> <br /> Package Incldues:<br /><br /> 1 x CO2 Bubble Counter or 1 x Air Check Valve