2b single mounting facility thread class 12.063" overall length 2.344" overall width 32 single mounting facility thread quantity per inch tap, square frame unc single mounting facility thread series
2a single mounting facility thread class 0.310" single mounting facility thread length 5.165" overall length 1.620" overall width 32 single mounting facility thread quantity per inch two 1/4-20 unc-2a thd mtg studs on rear spaced 1.500 in. c to c tap, circuit selector uns single mounting facility thread series