“D. K. MILLER LOCK CO PHILA. PA PATD JULY 26.70.” – No Pins – Master Keyway. “D. K. MILLER LOCK CO PHILA. PA PATD JULY 26.70.” is stamped on the obverse of the body. The reverse and the left edge of the case is plain. There is a second keyway that accepts a master key.Patent # 105710. (M-460).