Make an elegant curve line in the box-shaped aquarium * Glass transparency give superb appearance to your aquarium * Deliver clean water from the filter with appropriate water flow speed * Package Included: 1x Lily pipe inflow and outflow, 4x Suction cups According to filtration/hose size guides: A 13 mm lily pipe refers to an external diameter of about 13 mm of the glass pipe. The matching flexible hose size for a 13 mm lily pipe is typically the one with internal diameter ~12 mm (and external diameter ~16 mm). That is “12/16 mm hose” in some specs. For example, if your filter uses a hose coded as 12/16 mm (12mm internal / 16mm external), then a 13 mm glass pipe is appropriate. If your filter hose is larger (say 16/22mm) then you’d need a larger lily pipe (~17 mm) instead.
