OMEX 4-Inch Pocket Brass Calipers | Inside & Outside Measurements | High Precision Dual Graduation Design | Made from Solid Brass | Professional Quality | for Mechanics, Hobbyist, Crafters. A handy pocket caliper, made from solid brass. Close tolerance dovetail design ensures smooth motion of the caliper and provides accurate measurements. Graduated in both imperial and metric graduations with a least count of 1/16" on the imperial scale and 0.1 mm on the metric scale, these are ideal for use by mechanics, hobby crafters etc.