The open preheat cap for flair 58x allows you to preheat the unit without electricity. The cap also enables the brew head to affix firmly to most gooseneck kettles while the water heats, steam, and residual heat preheat the brew head. Specifications: Suits Flair 58x Silicone Open Cap Directions: Place the cap on the allow the head to preheat on your kettle Once preheated, remove the cap Place brew head on portafilter base Happy brewing!