M.C. Miller B3-A1 Digital Multimeter

Got this M.C. Miller high impedance digital multi-meter for sale. It's the model B3-A1 and comes in the rugged carrying case with the instructions right there on the lid. These are pretty standard for corrosion testing and pipeline work. It looks to be in decent shape but I havent tested it. I don’t really know how it works to be honest. It was given to me with a bunch of other things. Comes with the leads shown in the photo. Good solid piece of kit if you do field work.