Tactile Caliper (Braille)An ingenious invention, this caliper is similar to a caliper tool a sighted person might use except it is in braille. * As you slide the measuring tool down the ruler, the braille refreshes. * This plastic caliper measures to 1 16 of an inch and is 15 inches long, which makes it easy to take on the go. * Add this incredibly useful device to your tool kit at home, in the garage or for your next big project.