6" Vernier Dial Caliper
I use this for taking Critical Measurements during the natural trim and booting. I've used this particular model for over 25 years.
"General Tools 6" Fractional Dial Caliper has a fiberglass reinforced plastic body which allows accurate reading of inside, outside, depth and step measurements. The easy-to-read dial is color coded to highlight graduations in both .01 inch and 1/64 inches, and features a no-glare lens cover. Additionally, the Plastic Dial Caliper is marked with inch and millimeter graduations on the bar scale and a fractional conversion table on the reverse side."