The Duplex watch escapement, invented by Robert Hooke in 1700, went through improvements by Jean Baptiste Dutertre and Pierre Le Roy before being perfected by Thomas Tyrer. It was a challenging escapement to make, but it offered higher accuracy than the Cylinder escapement. The Duplex escapement was used in English pocketwatches from 1790 to 1860. This particular watch features a single piece enamel dial, a 3/4 plate English styled movement, and a unique independent bridge that supports the balance spring above the balance cock. The balance assembly can be removed to reveal the hidden Duplex escape wheel. The watch also includes a thermometer mechanism, driven by a rack and pinion system.
https://www.thenakedwatchmaker.com/blog/2021/6/21/a-special-escapement