Midwest Products Big Hobby & Craft Square has a 6 inch square with multiple types of measurements including both imperial and metric standards.
6" (15cm) ruler
45º edge with built in protractor in 5º increments
Dowel / Tubing Identification Gauge from 1/16"to 3/4" (2mm to 10mm)
Strip identification guage from 1/64"to 1/2"(.5mm to 10mm)
Built in stop rail for quick alignment to the work surface
90 degree square for perpendicular assemblies
One Big Hobby & Craft Square