Founded in 1960, PPM, Inc., designs and manufactures high-precision electronic test instruments--including resistance standards, ohmmeters, and other products. The PPM name was selected to indicate the extreme accuracy of the equipment offered, with errors categorized in "parts per million." PPM customers include NASA; NIST; the U.S. Army, Navy, and Air Force; Boeing; General Motors; General Electric; and many other industrial and government laboratories.

PPM Inc. contact information: 23500 Mercantile Rd. Cleveland, OH US 44122

TestMart contact information: 1000 Cherry Ave., Suite #100, San Mateo, CA 94404 (888) 665-2765