These pipes, Inflow Pipe and Outflow Pipe , are made by glass. This is transparency so it does NOT disturb the appearance of aquarium and it is suitable for water plant layout because of good water current for it. Also, Out Pipe is special shape so you can use for aeration as well when you put and fix half of Out Pipe from the water surface. You can prevent deficiency of oxygen during the night.
 
Moderate water circulation evenly within the aquarium is essential to maintain the water quality and prevent algae appearance. However excessively strong out flow of the power filter works negatively, hindering healthy growth of aquatic plants. Lily Pipe Outflow is hydro-dynamically designed to create a moderate circulation of water within the aquarium ideal for the growth of aquatic plants. Sliding Lily Pipe Outflow above the waterline allows it to also serve as an aerator which eliminates oily surface film.