Mr Aqua CO2 Glass Bubble Counter and Diffuser As the CO2 enters the diffuser you can count the CO2 bubbles and then the diffuser will create small CO2 micro bubbles to be taken into the water and for the plants to take in.
Convenient CO2 diffuser.
Glass blown
Glass diffuser is a long lasting way of adding CO2 to your aquarium. 
$159.00 AUD
$46.95 AUD 
