Set of glass Inlet/Outlet ball type 20mm. It is designed specifically for the aquarium using high-quality, laboratory grade glass, with maximum strength, durability and visual clarity.Achieving the perfect fusion of art and function, these outlets have such a high transparency in the water they are almost invisible, allowing you to showcase your aquascape to its full potential. The glass outlet pipe has a graceful curve design and creates an ideal water flow for the growth of aquatic plants. The ball shape provides a moderate water flow.. The Inlet pipe carries water from the aquarium down to the canister filter. Absolute’s unique design places intake slits across wider distances on the stem. As a result, it pulls in water from multiple depths spanning a wider range of the water column. This improves water circulation and allows particles suspended higher in the water column to readily enter the tube to the filter.