NICREW Aquarium Lily Glass Pipe Inflow and Outflow with Surface Skimmer 13mm 17mm for Aquarium Planted Tank Fish Tank Filter Inflow Pipe Glass Inflows are designed to transport the water from the aquarium to the external canister filter. This simple design glass pipe has suction slits. For use with a frame-less aquarium tank. Due to its slit form, it have advantage of not to suck in the withered leaves easily. This improves water circulation. But please make sure to remove the leaves stuck on the suction slits. These pipes 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. Outflow Pipe This outflow pipe bringing clean water from the filter backto aquarium. 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. Usage Sliding Lily Pipe Outflow above the waterline allows it to also serve as an aerator which eliminates oily surface film. Also you can prevent deficiency of oxygen during the night. Main Features: 1. Acrylic Surface Skimmer well made, would not hurt fish and shrimp. The surface skimmer efficiently skims dissolved organics and other waste material from the water?s surface of your aquarium. 2. Adjustable Intake Flow Removable, rotate around to adjust flow. 360-degree intake float is positioned consistently at the surface and the ?ow control valve enables you to increase or decrease flow rate to your filter. 3. Deliver clean water from the filter with appropriate water flow speed 4. Made of High Quality Give superb appearance to your aquarium. 5. Thicker Tube Wall 2mm thickness, more stronger. Note: 13mm fits for 12mm inner diameter water pipes. 17mm fits for 16mm inner diameter water pipes. Please Note the Inflow and Outflow Port Diameter. If you have any questions, please feel free to contact the seller! What's in the Box: 1 * NICREW Inflow or Outflow Pipe Or Inflow and Outflow tube set. FREE SHIPPING IS INCLUDED!