In this penultimate step, the mainspring barrel becomes a closed affair. This way, the spring stays where it belongs and can do its work undisturbed. Without it, nothing works. Without energy, the watch cannot tell the time. However, in order for it to work at its full capacity, the spring core in the barrel must have an appropriate amount of play. It is essential that this be checked. If energy is lost here, then the balance oscillates sluggishly, the timekeeping accuracy suffers, and the watch can even stop ticking sooner than it should. It's a good thing that our employees have a keen eye here. They check and adjust the spring so that the energy can be used with full efficiency. To the delight of all concerned.