Neat lock!

This "US" warded brass padlock was made around 100-110 years ago. Most aren't marked, but Franklin M. Arnall's book,
The Padlock Collector, identifies the maker as the E. T. Fraim Lock Co. of Lancaster, PA. Although it's sometimes listed as a lock from a U.S. mail bag, and on eBay some sellers have also called it a military lock, in fact it was a retail item sold in hardware stores and mail order catalogs— not an official government lock. "US" was just the model name. When RFD mail delivery began, many people bought these "US" locks to use on rural mailboxes. There were also locks with "MAIL," "RFD," "RR" (for Rural Route), and other official-looking names that were sold for the same purpose.