PURPOSE: A switch is provided to offer the effect of improving the quality by preventing the direct friction of a cap against the knob by maintaining the interval with the knob by comprising a plurality of protrusions on the external surface of the cap. CONSTITUTION: A hollow cylindrical cap holder(20) is connected to an encoder(1) and a potentiometer. A hollow cylindrical knob holder(40) comprises an upper holder hole(42) and a lower holder hole(44). A hollow cylindrical knob(60) is expanded toward the top of the knob holder. A cylindrical cap(80) is arranged on the inside of the knob with an interval.
