The function of pedals of the PETROF 135 K1 upright piano

Right pedal works standardly as a forte pedal. It lifts up all the dampers. That means when the right pedal is pushed down, all the played tones sound till the pedal is released.
Left pedal works standardly as a piano pedal. When it is pushed down, all the hammers are moved closely to the strings. Playing the tone, the way of hammer is shorter and hammer strikes the string with smaller energy. The tones are weaker.
Middle pedal controls the prolongement rail. When one or more tones is played and held (pressed keys) and the middle (prolongement) pedal is depressed, then the lifted dampers are captured and held up, even when these keys are released. That means these dampers do not dampen the strings played before and the tones still sound, even when these keys are released. When the middle pedal is pushed, it is possible to play other tones, which behave standardly. When the pedal is released, the captured dampers move back to the strings and dampen the prolonged tones.
Function of moderator is controlled by hand lever, placed left on lower side of key bed. When you move this lever by hand, the moderator rail moves down and weakens the sound and change the color of tone.