Have you ever been at a pub trying to measure the head on your pint, only to have others around you laugh at your pocket 6" scale? I've found the solution that nobody asked for.

It's based on a printed card version made by a popular stout producer in Ireland, but I made some changes to make it prettier.

The scale is in millimetres, and works quite well as a two-tone object. I printed mine in clear purple PLA, but any filament should work.