The temperature could be warmer.

After 15 minutes the water temperature of the cup on the warmer dropped to 154.2°F and the water temperature of the cup on the table dropped to 144.1°F.After 30 minutes, the water in the cup on the warmer is 143.12°F and the water in the cup on the table is 125.4°F.After 45 minutes, the water in the cup on the warmer is 138.2°F and the water in the cup on the table is 114.6°F.From then on, the water in the cup on the warmer temperature stays at around 131 °F.I tried drinking the water at this temperature (131 °F)

I did buy some mug covers and my coffee stays perfect drinking temperature

it can keeps my coffee at the perfect temperature(not too hot to drink, but warm enough to

I’m a slow coffee drinker，This little thing appealing to keep in desk all day, and most importantly it keeps your coffee literally as hot as when you made it