If you've ever played with Eagle PCB, you know that silk screen indicators are one of the most important aspects of your layout. We created this board to illustrate various text sizes and ratios (text width). You may use size 0.020 text with a ratio of 8% on your PCB layout, but as the reference board demonstrates, you really can't read it. We also included various drill sizes and trace widths but they are not completely accurate - the manufacturer increased the really small trace widths to avoid DRC violations. This is a great board to quickly determine the best size and ratio for text, drill sizes, and trace widths when creating your next design.
Based on 1 ratings:
I keep this board in my wallet and it is a good buy if you use eagle. Use this board when you're designing something with Eagle (or Altium, etc.) and you want to put your traces, drills, etc. into scale. Only use this as a rough estimate, but not for exact measurements, because some measurements are a bit off. I've had this little thing for quite a while now and the bare metal has started to corrode a little. :/ Even thought there is a hole in the corner, it is still a bit too big for a key-ring, but it is almost a standard credit card size, so it will fit into your wallet. I like this thing a lot and it follows me wherever I go, and I can really say that this thing is a good buy.