Perforated metal patella (knee) splint with a “LEE'S PATENT / OCT 30TH 1888 / LEFT” inscription. This was made by the J. E. Lee Co. Company, a firm in Conshohocken, Pennsylvania, that was begun by John Elwood Lee (1860-1914), and that offered various medical and surgical apparatus.
Ref: J. Elwood Lee, “Manufacture of Sheet-Metal Splints,” U.S. Patent 376,666 (Jan. 17, 1888).