Tera 350ml HOT Stainless Plain Lazy Auto Mixing Tea Coffee Cup Self Stirring Mug Office Home Outdoor Gift Novelty Just press the button on the handle to do self mixing, easy and convenient. Mute mixing impeller and sealed mug cover, no need to worry about liquid splashing. Material: stainless steel/food grade plastic. High-quality stainless steel and food grade plastic made, safe and durable. Battery requires: 2 x AAA battery (NOT included). Dimension: approx. 16 x 8.3 x 6.4cm.