This is a MASTECH MS2108A 400 AC DC Current Clamp Meter. ~$45 Amazon
I got this tool to do some home AC low voltage troubleshooting (something is blowing the 3amp fuse for the 24V transformer)

Anyway , its also a nifty tool for troubleshooting current draw...The pcitures below show the alternator/generator puts out about 30amps DC, from the battery to the under hood fuse box goes about 27 amps and with the vehicle turned off about .6 of an amp... (that was shortly after it was turned off, I don't know if all RAP was off)

It is Chinese make, in fact the box is all in Chinese, but the meter itself is is in engrish, it comes with a nice cloth padded carry case and meter probes/leads
It will also measure voltages, resistance and continuity with tone...and claims to also measure frequency...

 

they work great with this inexpensive tool.
Electronic Specialties Inc. Professional hand held automotive test equipment. Automotive Multimeter