A prototype instrument has been designed and built which demonstrates an ultrasonic pulse echo technique of measuring metal thickness in the range .010 to .080 inches. Extension of the range of measurement on the thick side appears straightforward, however, transducer frequency response considerations may limit the extension of the method for very thin sections. The instrument is based upon the principle that sections, when driven by pulses of vibratory energy, resonate at frequencies dependent upon the thickness of the section.