H.P. ethanol compatible fuel lines for Cobra and Chuweng & many other mini scooters. provides and produces more pressure on fuel tank grommets helping to seal leaks & line i.d. is bigger on fuel supply so it assists in facilitating a higher fuel flow. purchase either with or without a replacement fuel filter or 17mm chuweng grommet and appropriate filter or Cobra 22mm grommet and filter we are now offering both style grommets! the ones that come in the top of the tank 15mm hole 17mm grommet and the ones that come in the back of tank 19mm hole 22mm grommet when ordering the fuel lines with grommet set up so we know which grommet to include. Select 15 mm or 19mm even if just ordering lines. By making size of grommet selection, that will let us know which size filter or grommet is needed if ordered/added