This dongle-sized thermal camera is astonishingly good

Thermal Master's P2 thermal camera.

I test plenty of phones, and I rely on a thermal camera to measure how hot devices get while testing. I use it the most while running extended gaming tests, as that's inevitably when a phone gets hot. This year's devices run hotter too, as evidenced by the Nubia Z70 Ultra hitting a toasty 59 degrees.

(Image credit: Harish Jonnalagadda / Android Central)