I searched the internet but I could not find any info on this doorknob. This was found in the stream behind the Mt. Washington Omni Resort. I'm not positive that it came from the resort but I guess the building was constructed in the early 1900's. It is brass and the threaded hole is not the standard 3/8ths hole, it is about 5/8ths of an inch. I have dealt with many older buildings and I have never seen a handle with a hole this large.