Crichton Coin Rolling Measuring Tools
Life (i.e., your carpentry or sewing project) throw you a curveball? Roll with it. Crichton Coins are simple measuring tools that roll around curves and complex design details to provide the accurate measurements that standard rulers and tapes - even the fancy laser ones - cannot.
This pair of Crichton Coins, one with imperial and the other metric measurements, comes from Silver Fox Tools. They are made of solid brass with engraved markings that won't wear off over time. A bullet start mark designates where to place the coin to begin rolling and tallying your inches or centimeters. The imperial Crichton Coin covers 6" per rotation, and the metric 15cm.
Crichton Coins themselves are 1.9" / 4.9cm in diameter, and come either individually or as a set with a hand-stitched leather pouch.
Muchas danke to Core77.