Wow what a bargain! This powerful air pump can produce 1,800 litres of air per hour - enough for a pond sized 12,800 litres (10,000 if keeping fish and 5,000 if keeping koi). Quiet in operation, the premium build quality of this pump can be felt from its sturdy aluminium casing to the quality accessories and fitting supplied in the box. Running an air pump provides additional oxygen into the pond. This is essential for the health of your fish - especially in the summer when oxygen levels are depleted. Additional air also leads to additional water circulation and a healthier pond. Please note that a 4-way chrome manifold is included in this set. This means that the air flow can be direct to just 1 airstone or 4 and everything in between! It also means you can use the taps on the manifold to infinitely control the amount of air channeled through each port.