Automatically turns on when put on the heating surface Warmer has non skid feet for stability Mug Dimensions: 3.81″ H x 4.78″ W x 3.05″ D Warmer Dimensions: 1″ H x 4.83″ W x 4.83″ D Power Source: Corded electric with automatic on/off when mug is placed Care & Safety: Do not immerse warmer; mug is hand wash only Material: Ceramic mug with plastic warmer base