French Stölzel valve horn with two valves, after Antoine Halary c. 1830

This two-valve model was one of the earliest valve horn models used in France, developed in the 1820s.  This configuration was developed in collaboration with Jean-Joseph Meifred, a pioneer of the valve horn in France who developed a technique of playing using both hand stopping and valves, which he taught at the Paris Conservatory and documented in a Method book. 

The Stölzel valve was an early piston valve design, developed by Heinrich Stölzel, and patented prior to 1820. It was a predecessor of the Perinet piston, which improved on the smoothness of the air flow of the Stölzel valve, which has abrupt right angles.

Prices

French Orchestra horn with two Stölzel valves = $6,865

Crooks

G = $286

F = $411

E = $426

E flat = $438