This bench-top engine diagnostic unit is a Sun Electric Corporation Master Model Motor Tester, manufactured in Chicago, Illinois. The device features a blue painted metal housing with a hammer-tone finish and a stylized header at the top displaying the company name in red lettering with sun-ray graphics, flanked by silhouettes of a streamlined bus and a sedan. The unit is composed of four modular diagnostic sections. The Coil Breaker Unit 30D includes a coil meter, a visual breaker point viewing window, and controls for coil set regulation and 6V/12V electrical systems. The Condenser Vacuum Unit 20D features a condenser meter and a circular vacuum gauge that measures engine vacuum and fuel pump pressure, with associated capacitance and resistance selector knobs. The Tach Dwell Unit 10D contains a tachometer for measuring engine speed in hundreds of RPM, a dwell meter, and a lobe selector for 4, 6, and 8-cylinder engines. The Combustion Booster Unit 50F includes a combustion meter for measuring efficiency across gasoline, propane, and butane fuels, with battery and combustion regulators. The unit retains multiple original Bakelite control knobs and individual glass-faced meters. Several metal identification plates are present, stating Sun Electric Corporation, 6323 Avondale Ave., Chicago 31, Ill., U.S.A. The original testing lead wires with alligator-style clamps are attached. 47 in tall.