The Certikin Skimmer Vacuum Adaptor otherwise known as a Vacuum Kornea sits securely on top of your Certikin Skimmer Basket. This will then allow you fit your vacuum hose onto the pipe section of the Kornea. The purpose of this tool is to trap leaves and other debris in the basket whilst you are vacuuming. If this item is absent you will have to remove your skimmer basket whist vacuuming and plug the hose into the bottom of the skimmer. The disadvantage of this is that the debris will travel through your pipe leading from the skimmer to your pump possibly causing them to become blocked.