Incabloc is a common shock protection system used in mechanical watches, recognizable due to its lyre-shaped spring.
Incabloc was developed and trademarked in 1933 by Portescap. It prevents a watch balance staff from breaking by allowing it to move slightly, both laterally and vertically, using a spring-mounted jewel setting. Incabloc is easy to recognize due to the golden shield- or lyre-shaped spring clip around a ruby at the top of the balance. This is hinged, allowing the shock absorber to be lifted in place so the cap stone and the rest of the anti-shock pivot can be removed.
Incabloc makes both removable and hinged anti-shock mechanisms