Labeled ASI , Advanced School Inc. . Made by CAL Hawk , California , 1972 Now Actron? See photos for condition and contents The gas analyzer heats up and responds , but accuracy unknown. I checked the voltmeter , working , so the rest of the engine analyzer should be ok? Needs a battery to function, not supplied. Comes with manuals as shown. Priced cheap at $35 plus shipping, AS IS , not returnable. USPMO or PayPal , buyer handles fees Send a private message Thanks Roy