One side of this 12" ruler is calibrated in sixteenths and tenths of an inch; the other side, in centimeters and millimeters.
I ordered two extra, since my kids were always wanting the single one we had and ignoring the plethora of wooden rulers that stay on the shelf. Now my 15-year-old can keep one with his stuff, someone else can have one, and I'll still have one left for math lessons!
Best I've come across
I ordered a second one of these rulers because they are great. The material is good quality and yet the edge is not too thick. I especially like that one side of inches is divided into tenths. You just can't find that much at all. It's been a very useful ruler for our family.