Jardin Round Mineral Bubbles Air Stone for Aquarium, Blue, Pair of 5

I bought these to aerate a 600 gallon fish pond. Using a Tetra 26076 Whisper Air Pump, 300 and a bit of hose several of these were were sunk to the bottom of the pond. I was pleased to see that the size of the bubbles were much smaller than a previously purchased air stone. They don't seem to disturb the fish as much. I had no problems with the stems coming off while installing these but at these price I bought 2 sets of 5 to have spares. It seems the stems are set up for 1/4" tube as the slightly smaller metric tube was a tight fit.