The air pump works great, but i wouldn't use this to aerate a tank larger than 5 gallons by itself. Takes up almost no space and fits on the side of the tank quite nicely. I have it hooked to a sponge filter for a 1.

The bubbles are not too much and not too little. Pumps plenty of air. The only drawback is it does not have enough power to produce air bubbles if you are wanting them to come out of 2 different areas in your tank.

I'm just surprised how responsive both of them are when we enter after work or waking up in the morning. They make no noise even with being against the glass inside the terrariums. Good value for the money and was super quiet.