Regarding the question about the Collins meter; I have a similar question........ I have what appears to be, a near new 2 1/2" square Collins Radio Company meter rated 0-300ma DC......CRC #450 1300 00, also marked 03120. It appears to be a Simpson movement with vertical bars on the front of the case. Any one know what equipment it may have been used with? Thanks/73/jim/W0JJL