Brass rotary registered mail lock manufactured by William Smith & Frederick Egge. The body front is marked “US / THRO / REG’D MAIL” and the back “H526.” The shackle back is dated “1881.” This rotary lock used a standard key issued to post offices and Railway Mail Service employees handling domestic registered mail. Each registered mail lock of this style was referred to by its serial number as well as the four-digit rotary number that appeared in a side window (covered by a brass flap in this example). This lock accepted a quill-style key and has a round keyway on the bottom of the lock and was in use until 1884.
English