This .01µF polystyrene capacitor can be used for a guitar tone circuit, and it's a common choice for a good balance of treble reduction and maintaining some higher frequency content. Polystyrene capacitors are known for their high quality and low loss characteristics, making them a good choice for audio applications.

Treble Control: This .01µF capacitor will roll off some of the higher frequencies when the tone pot is turned down, helping to create a warmer, less bright tone.

Balanced Frequency Response: This .01µF value provides a good balance between reducing treble and still allowing some high-frequency information to pass through, even when the tone knob is turned down.

Polystyrene Quality: Polystyrene capacitors are known for their excellent stability, low loss, and good quality.

In summary, this .01µF polystyrene capacitor mfg. by Evox can be a good choice for a guitar tone circuit because it provides a good balance of treble reduction, maintains some higher frequencies, and is made from a high-quality material