Signedplate on inside of lid: DESIGNED & BUILT FOR / CRUFT LABORATORY / BY / HENDRICKS & HARVEY / HARTFORD, CONN.
on face of meter: WESTON ELECTRICAL INSTRUMENT CORP., NEWARK, N.J., U.S.A. / MILLIAMPERS D.C. / WESTON / MODEL 506 TYPE F01 / PAT. 1,579,849 1,597,256 1,635,595 1,661,214
Inscribedetched on inside of lid: CRUFT LAB. / MARCH 1, 1933
Related Workshttps://www.radiomuseum.org/r/hendr_harv_single_signal_receiver.html