Gentle Water Flow for Planted Aquariums \nDymax's Crystal Glass Lily Pipe allows filtered water to gently flow into the aquarium and provide proper aeration throughout. This glass pipe set comes with both the inflow and outflow pipes and is available in two sizes: 12/16 diameter and 16/22 diameter. \nHighlights: \n\nMade of high-quality crystal quartz glass\nQuality handcraft selection\nBuilt-in water surface skimmer\nIncrease water movement\nPrevent accumulation of oil on the water surface\nReduce excessive CO2 lost\nDesigned to gently cascade water into the aquarium without disturbing the aquascape\n\nIncluded in the Package:  \n\nOne Outflow Lily PipeOne Inflow Lily PipeFour Aquarium Suction Cups