H. Lenhert, Philadelphia, was in business from 1867-1914. Henry G. Lehnert (1838-1916), founder of the company, arrived in Boston from Saxony ca 1860 with his brother Carl. Early Boston directories indicate that they both worked either for E. G. Wright or for Graves & Co., then joining Freemantle & Co. before establishing business as Henry Lehnert & Co. In 1866 Henry moved to Philadelphia and started his brass musical instrument manufacturing business. He held a patent for the tapered cornet leadpipe and frequently used Allen rotary valves and German silver in the manufacture of his instruments, which had a very good reputation for quality. From 1876 through 1914, his instruments bore the trade name "American Standard".
This is the one I own, made of German silver with Allen valves, ca 1870.