Key Features Highly Porous Air stones Can be used in Ponds and Aquariums Provides essential oxygen in the water and helps to maintain healthy fish Can be used with most airlines and air pumps Pack of 2 - 200 x 27mm, takes 8mm airline Pack of 2 - Pisces 200mm Round Air Discs help to add oxygen to your pond or aquarium, helping to enrich the water for the overall benefits of the life inside. Adding an airpump and airstones to a pond or aquarium set up is a key component of any filtration system. Air pumps work by circulating air and producing oxygen that is then dispersed into the water by a porous air stone or disc. This ensures vital air is getting to the fish and plants inside to promote healthy living. The Pisces Round Air Discs can be connected to any air pump inside the pond or aquarium, and help to provide the beneficial air bubbles that add oxygen to the water. The stones are encased with plastic base to ensure they can be placed safely on any surface with the porous top of the