Hand Crafted Each piece is unique. Superior quality. Durability & Strength Using only the highest quality, laboratory-grade, borosilicate glass ​for maximum strength, durability. Visual Clarity The glass pipes make your aquarium look less cluttered. It's a huge upgrade in term of aesthetics. Glass Violet Pipe Outflow Violet glass outflow pipe designed for an external canister filter. The unique shape of the outflow section can create adequate flow without placing burden on water intake. It creates water flow suitable for keeping fish that prefer moderate water flow, such as cyprinids and characins, in an aquatic plant layout. In addition, the outflow pipe provides aeration depending on its placement. Its narrower outlet provides slightly downward water stream. Usage 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. Also you can sliding Violet Pipe Outflow above the waterline allows it to also serve as an aerator which eliminates oily surface film. Size 13mm for 12/16mm (1/2'' ID) tubing, for aquaria with a length of approx. 24" to 36" 17mm for 16/22mm (5/8'' ID) tubing, for aquaria with a length of approx. 47" to 71" Tips for install: Always wet the glass tubing before inserting the silicon or rubber tubing to avoid damaging glasswares.