F-4 the fazer is with only 1 minutes first heat-up time which makes practically no waiting before using. 
The large heater tube reduces remarkably the chance of heater clog. The quick connecting design between the fluid tube and the tank saves time while changing the fluid tank. 
The most splendid feature of F-4 is that now it can be controlled with multiple languages! It is always our goal to make our products as user-friendly as possible to every user around the world.