Two weeks ago, MB&F presented the HM3 Frog X 10th-anniversary edition. Today, the 10th-anniversary celebration continues but this time for the HM4 which also made its debut in 2010 when the HM3 Frog was released. A decade ago, MB&F also shocked the watchmaking world with what remains to be one of the most radical horological machines ever created by them. We are talking about the HM4 Thunderbolt.