OTC designed the AMP Clamp/Multimeter, No. 3908, to allow accurate current measurements using clamp jaws. The clamp meter is well suited for testing starting/charging circuits, and provides easy access to current voltage and other key automotive measurements. Ideal for direct electrical testing, verification of automotive circuits and drivability related diagnostics, starting/charging system tests. The 3908 measures current in any AC/DC circuit up to 100 amps without interrupting circuit. The 22mm clamp opening size accommodates large gauge battery cables and can be used for testing started draw and alternator output.