PACKAGE INCLUDEDPackage includes 4 pcs air stones, 2 pcs T-Splitter. Note: air pump and air tube are not included^ Product InformationWenshall air stone is made of silicon carbide, which is good for fish tank and hydroponics. Size:1.6 x 0.6 inch / 42 x 15 mm(D x H), Weight: 1.14 oz / 32g. Jetting volume: 2 L/min. Perfect match with Standard 3/16 Tubing.^ EASY BE HIDDENRound cake design. Small size very easy to be hidden under the water. It won 39;t move when it 39;s working^ LONG USE TIMESoaking the air stone in the water for one hour before use. Brush the stone surface every 2 weeks, you will find that it can accompany you for a long time and save a lot of money.^ LIFETIME SERVICE Wenshall is a different kind of company that prides itself in providing the absolute best customer service in the industry. If for any reason you decide that this air stone set is not for you, send 1 simple email and receive a 100% money-back refund, absolutely no questions asked (in fact, you don 39;t even have to return the set)