Hamilton H-21

Hamilton's modified Valjoux 7750 with enhanced 60-hour power reserve (vs standard 42 hours). Features a custom H-pattern design on the oscillating bridge, refined kinematic chain from barrel to escapement, improved mainspring, and suppressed escapement regulator for optimal reliability and precision. Found in Khaki X-Wind, Jazzmaster Maestro, and Khaki Field Auto Chrono models.