Boss XTOFFY Collaboration Product Requires 2 AA alkaline batteries (not included) Convenient for frothing milk. There's a knack to using it, so be sure to read the back of the package before use. *This is to prevent milk from splashing. Coffee Goods Cafe au lait Boss Cafe Base Milk Foamer Toffee Milk Foamer Meringue Egg White Soy Sauce