This vintage round gauge is marked WESTON ELEC. INST. CORP. , Newark N.J. U.S.A. MR 35 W 001 AC AA AMPERES A.C. WESTON Model 476. It goes from 0 to 1 Amp. It measures approx. 3 ½ inches across and is almost 2 inches deep not counting the back screws. It is not tested and no instructions so sold as is. It includes the test wires and attaching screws. One wire has copper alligator clips and the other rusted steel clips. It is used with wear, rusted clips, test wire aging, damage and stains. The case appears to be black plastic possibly Bakelite.