A thin-bottomed mug will have the best warmer retaining performance. This coffee mug warmer not only slow down the cooling speed of hot coffee, but also heat your coffee up to 131 Degree F/55 Degree C, and keep this temperature whole day, which is neither too hot nor too cold, you can sip your coffee at any time, without waiting. Customize it with your logo or company name on the warmer coasters for maximum visibility and become your next promotional event! The price includes the shipping cost to ca. QTY over 2K by ocean. Rush and sample service is available. 100% gurantee for quality. Thanks.