The Hagen 12” Air Stone is 12" (30.5 cm) long and blue. This durable air stone diffuses water in every direction. It creates a dazzling underwater scene, increases surface agitation, accelerates oxygen replenishment, helps release carbon dioxide build-up, creates a wall of bubble and fits standard airline tubing The ELITE air stone is ideal for adding accents in any aquarium the air stone diffuses air, creating water movement. The ELITE air stone also increases surface agitation, accelerates oxygen replenishment and helps release carbon dioxide build-up. Simply connect the air stone to your airline tubing and place it in desired location.