E liquid is for the new generation of the electronic Shisha cartomizer which contains only E-Liquid inside without any sponge material. Shisha Pens are a Boiling permanent cartomizers. You will not need to change the cartomizer any more by just refilling the e-liquid inside. It is safer to smoke without burning of the sponge material. There is no burning smell any more. It contains much more E-Liquid and get much more effective smoke quantity with the new technology of cartomizer.