You carry a pen around religiously, but wouldn’t it be nice to have calipers always handy? If you owned a Messograf caliper pen from Cleo Skribent, you’d always have calipers.
Built into the retractable ballpoint pen is a 4″ Vernier caliper that measures in increments of both 0.1mm and 1/16″. The pen also functions as a metric screw thread scale and a tire tread depth scale.
Made in Germany from chrome-plated brass, the Messograf caliper pen retails for about $27 or so depending on the exchange rate, but you can find it as low as $20 before shipping.