Lee Valley Adjustable Hook Rule
Known in the trade as 4R rules, each of these has four different scales. One face has 1/8" and 1/16" divisions, the other 1/32" and 1/64" divisions. The four scales let you be as picky or as approximate as you wish. All have adjustable hooks, meaning that you can slide the hook fully to one side so that it clears the opposite edge. Accuracies range from +0.005"/-0.003" on the 6" to +0.007"/-0.004" on the 18" rule. The rules, made from 0.040" thick satin chrome-plated hardened and tempered tool steel, are etched and black filled for readability. Made in USA.