This lozenge shaped device is not only a USB power bank that can keep your mobile devices topped up, but is also doubles as a miniature heater that ... the Go Warmer is powered by a pair of ...

The MCH he chose was rated for 20 VDC at 50 watts — perfect for powering with USB-PD. The heater sits above the main PCB on a Kapton-wrapped MDF frame with a thermistor to close the loop.