often made by Tadiran comunucations and also Soltam systems , under part number 167-1139 

these three plates are steel and are cromate cadmuim plated , they measure 3.963 just under 4 inches long x 1 3/4 wide x 0.047 inches thick , they have two holes that are 0.440 inch diameter and are spaced apart by about 2 3/8 center to center , nice parts for many projects , see our store here on ebay we try to add new items weekly to our warehouse , thank you for visiting today , RWK