Improve your Groove The Electro-Harmonix Q-Tron - the phattest, funkiest envelope filter ever made! Features like switchable Boost and Filter Mix mode allow for an unlimited supply of all-new auto-wah effects that drip with attitude. Increased frequency response and improved signal-to-noise ratio make the Q-Tron perfect for use with any instrument. Bootsy Collins and George Clinton already have theirs. How about you?