There are pocket-sized electronics, and then there's the EclairM0. It's a 50 x 40 x 8mm (2" x 1.6" x 0.3") device that weighs just 15 grams (0.5 ounces). But it's a multifunction gadget with a small OLED screen, 14 buttons, a USB-C port, and support for over 10 hours of battery life. Among other things it can be used to take notes on the go, as a USB input device for a computer, or for other purposes.