This is my favorite diffucer because you can count the bubbles and it has a glass non return valve built in. Also has a reasonable sized ceramic disk. Helps to fill the diffuser with water first so you can see the bubbles through the spiral.

This is a good looking diffuser in the aquarium and I like the fact that is has a built in glass check valve which is not unsightly.

I have this connected to a DIY 5 liter system in a 48 galling tank. I am getting maximum absorbtion through the fine bubbles and my plants are doing great.

The diffuser works very well with a DIY CO2 system, very small bubbles. I have a 20 gallon long aquarium and my plants seem to be very happy with this diffuser.

Excellent diffuser for DIY CO2 systems. One or two hours after i connected my yeast CO2 system it start to release made many small co2 bubbles.
It's made from enough strong glass.