Early 30s rats with flat selectors

[snapmom]

Some flat selector switches showed up in the early 30s. The 31 cat shows a 1/2 No. 71 rat with a flat selector. The pics are from bottom to top. F7 date code 1930. F70 date code 1931. No. 71 date code 1931. this 71 has the screws in the faceplate, but the guts are different than the other 71s I have with the faceplate screws. This one has a heart shaped spring, an no hole in the faceplate for the paw. The 3/8 dr rats are not in any of the cats that I know of.