right the metronome works just like a wrist watch,.. the spring gives the energy to move the pendulum, but frequency is determined by the pendulum mass and lenght, as the balancer with spring does in the watch;and in fact, to change the frequency you move the mass along the slider;have a good fun with metronome ! .. personally, I could not use it since I was a child.. it puts too much pressure to me! merry christmas to everybody!