Various air stones to fit either 4mm or 3/8 air line. 

These high quality long life air stones are made from a refined ceramic compound. They produce very fine aeration and can be used in conjunction with any good air pump. All of the ceramic air products listed have plastic end housings which protect the air stone against abrasive contact from the surrounding surfaces.

50mm ball air stone - 4mm fitting - Ceramic

30mm x 130mm can stone - 4mm fitting - Ceramic

40mm x 170mm can air stone - 3/8" fitting - Ceramic

50mm x 200mm can stone - 3/8" fitting - Ceramic

50mm x 300mm can stone - 3/8" fitting - Ceramic

 

130mm round air stone - 4mm fitting - Ceramic

200mm round air stone - 3/8" fitting - Ceramic