Alumina Airstone - 1-1/2 in x 1-1/2 in x 12 in - 1/2 in NPT

3 times stronger than white silica airstones - Alumina airstones are ideal for large aeration situations like ponds. Pro-Glass design produces a finer bubble with no increase in pressure. Higher density means they're self-weighted and easier to add to any application. Cleanable with muriatic acid or chlorine. More resistant to ozone than standard air stones.