US Patent 12104829 Disposable devices for heating beverage containers

Disposable devices for maintaining the contents of containers, such as hot beverage cups, at or near a desired temperature for an extended period of time. The disposable devices include a sleeve having an inner surface, an outer surface, and a cavity that contains a heating element. The device is configured to define an interior passage that is sized and able to conform to an exterior shape of a container such that heat can be transferred from the heating element to the container. The device includes openings that allow air to contact and activate the heating element via initiation of a heat-generating reaction.