Heavy weight, quality constructed, steel/metal, Japan flashed, door knob back plate with skeleton keyhole, from Yale, circa 1910s.
Stripped of paint. See remarks regarding condition and photos for further description. 

Plate Measures:
7" Long
2 1/4" Wide
1/8" High (plate only)
1/2" High (with shank collar)
Shank Opening Measures:
5/8" Diameter (approx)
Distance from shank opening to top of keyhole is 2 1/8" (approx.) on center.
Please message with any questions!