Decription: Aquarium Glass Spiral Bubble Counter CO2 Diffuser For Planted Tank  Designed for fish tank、 simple and lightweight.   High quality Spiro shape glass bubble counter.  High transparency、 durable、 can use for a long time.    Compatible with pressurized CO2 tanks and DIY yeast bottles.    Gives your tank a great and special look than other normal bubble counters.  Uses the high quality glass manufacturing、 acid and alkali resistance、 without etching.   Beautiful bubble counter that helps you to estimate amount of CO2 release into your aquarium.    Bubbles moves along the Spiro upward、 and when it escape from the Spiro、 you can count bubbles per second.   Instructions:      Fill the counter with water      Connect the CO2 tubing to the inlet of the counter      CO2 gas from the pipe will create bubbles in the water      Count the number of bubbles per second to make calculation      Counter can be placed outside of the tank. Use the suction cups stick to the aquarium glass.      Specification:   Material: Glass   Color: Transparent   Size: 155x22mm(LxD)  Package includes: 1XBubble Counter With Suction Cup