AQUANEAT Air Stones for Ponds 2 Inch, Long Lasting Aerator Oxygen Diffuser, Air Pump Accessories for Aquariums, Fish Tanks, Hydroponics and DWC Reservoirs 4 Pack

They all wok and sink to bottom of pond. Provides air for fish.

Works as described. I used two in my outdoor pond and blow a lot of bubbles. Would buy again.

I bought these because they are much larger than the ones I have right now. I use these in my septic tank because they put oxygen in the tank and thus helps the contents to biodegrade. These stones are supposed to give real tiny bubbles and put more oxygen in the tank.(I read that if you put oxygen in your septic tank that it will make the system more efficient. The large $1500 ones they sell will actually ruin your septic system so I have been using a $20 fish tank bubbler for several years and so far my tank is working very well.)

I can watch pond and make sure there is air circulating in winter when iced over

Nice bubbler for hydroponic gardening. Heavy enough to sit on bottom and not float around. Keep water moving. Pleased with product and the price. Good value

I bought these for my sons 110-gallon pool pond he built. Fish are thriving in the water now for about three weeks and his tank is even outside in the northwest Florida heat. Highly recommend these for your tanks.

Bubbles only come out of the top on all 4

WORKED GREAT IN MY OUTSIDE FISH POND