This product is a set of ring-type drainage pipe and J-type water absorption pipe.Both are made of high transparency glass, so your aquarium will look beautiful and clean.The drainage part is ring-shaped, and the water supply can be weakly distributed left and right with the ring-type outlet to create a suitable water flow for small aquariums. It is also suitable for growing aquatic plants because it allows a soft and moderate flow flow flow in the aquarium. Pipe Diameter: 0.5 inch (13 mm) External Filter, Compatible with standard hose size inner diameter 0.5 inch (12/16 mm) (0.5 inch (12/16 mm) *If the hose is hard to get in, please put the hose in hot water and put it on.