When I put the cup in the microwave to heat up my coffee for 30 seconds the cup came out with black scorch marks on it. I checked the label but there's nothing that says it's not microwave safe. Nice basic cups otherwise.
Chose these over the ones with lids that I usually get because we don't always need a lid and have enough of them leftover that cups-only is fine this time. Sturdy and never had one leak.