The EXAR PN-04 Pig Nose is an envelope filter for guitar and bass.
The dynamics (or volume 'envelope') of the input signal controls the frequency of a bandpass filter; the louder the input signal the brighter the tone, the quieter the input signal the darker the tone.
Wah rise time (attack), filter sensitivity and effect depth can all be adjusted for a wide variety of auto wah sounds, to suit different instruments and playing styles.
Controls
ATTACK: Adjusts of the filter attack (rise) time
SENS: Adjusts the filter trigger sensitivity
DEPTH: Determines the effect level in relation to the clean signal
EXAR Effects 
