The Megger 35871 USB/RS232 adapter for BITE 3 series is for connecting the BITE3 battery impedance tester to a computer that does not have a serial port. The adapter plugs into the USB port on a computer and then the BITE 3 RS232 data cable (sold separately) plugs into the adapter. The adapter has a 3' (10 m) extension cable and weighs 2 oz. (56.6 g).

Battery testers are used in the industrial, commercial, medical, telecommunications, aircraft, power utility, and military industries to detect the health of a battery. They can measure conductance, impedance, voltage, and current, among other parameters. Battery testers are designed for specific types of batteries, such as lead-acid, nickel-metal-hydride (NiMH) and alkaline batteries. Some testers require a load to be applied to the battery during testing, and some do not. A variety of test leads with contacts, probes, clamps, clips, and other connectors can be used to connect a battery to a tester. Since different testers can measure different parameters to calculate battery health, it is important to use the same tester for consecutive tests on a single battery when analyzing changes in battery health over time.