"The Adafruit Feather are a complete line of development boards from Adafruit that are both standalone and stackable.
They're able to be powered by lipo batteries for on-the-go use or by their micro-USB plugs for stationary projects.
Feathers are flexible, portable, and as light as their namesake.
Technical Details FeatherWing OLED - 128x32 OLED Add-on For All Feather Boards very readable due to the high contrast of an OLED display dimensions: 22.9 x 50.9 mm Display area: 25.8 mm"