HotSmart Keep Hot Mug Patented 12 FL OZ - Preheat ONLY 30 SECONDS; coffee will not get cold (Can be used for gravy too) SAFE HANDLING Integrated heater keeps adding heat to the coffee at a controlled rate PATENTED heating device integrated. Preheat a couple times before using to get rid of residual odors Larger handle. Just microwave 30-45 SECONDS to store ENOUGH heat; tested for years AS CLAIMED OR YOUR MONEY BACK GUARANTEE;