Essex mantel clock mfg. by Waterbury Clock Co.

Essex mantel clock mfg. by Waterbury Clock Co. Chimes and I think it has two key wind up. It is 8" wide by 12" tall and 4-3/4" deep with a wood casing. Brass clock mechanisms. I am not sure if it works, we are missing the key. The serial number is on paper and has worn off. It looks like it is a six digit number beginning with 81. Just wondering about the approximate age or any other info. Thanks