Alumina air stones for garden ponds, koi ponds, and water gardens are much stronger than silica air stones. Each Alumina pond air stone is self weighted and has a threaded fitting embedded into the air stone which is much stonger and less likely to break.
Two sizes to choose from:
|Alumina Pond Air Stone||Dimensions||Fitting Size||Price|
|6"||1.5" x 6" Long||1/2" Male Pipe Thread||$29.99|
|9"||1.5" x 9" Long||1/2" Male Pipe Thread||$29.99|