Autel's AutoLink, No. AL439, doubles as both a code scanner and an electrical system tester, performing many of the same functions as a battery tester. Supports all 10 modes of OBD II for a complete diagnosis. Featuring the unique patented One-Click I/M Readiness Key, graphing digital Multimeter, starting and charging system tests, TFT color display, and built-in speaker. This toolcan streamline automotive service and help ensure rapid, accurate diagnosis and timely repair, according to the manufacturer.