4 and 5 mm wrench (spanner)
I bought a metric wrench set that only included as small as 6 mm. So I made one. I printed with the makerbot which doesn't have as fine a detail in x and y so the model is really a 4.3 and 5.3 mm wrench which prints a tight 4 and 5 mm span.
I used sketchup2015 and included the model too.