The Chicago Electric Power Tools BATTERY And ALTERNATOR TESTER (Manufacturer Part Number: 66842) is a reliable tool designed to test the quality of batteries and alternators in vehicles. This product, manufactured by Chicago Electric Power Tools, ensures that batteries are functioning properly and that alternators are producing the necessary power for optimal vehicle performance. With this tester, users can quickly and efficiently diagnose any issues with their vehicles' batteries and alternators, ensuring smooth and reliable operation.