Synchromesh gears are generally used by modern-day autos inside the gearbox, which synchronizes the rotation of gears which might be messed. This type of gear removes the chance of equipment clashing and would make the shifting process a lot easier. This gearbox is someway similar to a constant mesh gearbox. https://automobilegearbox18495.theideasblog.com/34639872/automobile-gearbox-an-overview