All of these melamine pieces feature non-skid vinyl feet to prevent slipping. All dinnerware is dishwasher safe and should be used in the microwave for no more than 90 seconds. Note: Do not pour boling water directly into any insulated drinkware. Let the fluid cool for a few minutes and place a spoon in the mug to absorb the heat energy from the fluid. Failure to do so can result in the mug cracking.