Check the listing for details. Used Electro-Harmonix EHX XO Micro Q-Tron Envelope Filter Guitar Effects Pedal. Condition: Used. Listed at 91.99 USD. Used Electro-Harmonix XO Micro Q-Tron Envelope Filter Guitar Effects Pedal.Mint, with all original packaging!Orders placed before 12:00 PM Eastern Standard Time will ship same day! Orders placed after 12:00 will often ship same day as well, if not, they will ship next day.International orders: Please note that you will be responsible for any applicable customs fees or import taxes!Check my feedback and bid with confidence! The Micro Q-Tron is a smooth envelope filter with a funky wah-wah tone. The filter is controlled by its internal envelope follower, analyzing the volume of your notes and the dynamics of your playing to directly sweep the filter's center or cutoff frequency. A stronger attack or louder note will produce a wider frequency sweep while softer playing produces more subtle effects. Use the Q control to make the effect more dramatic. Specs: True bypassDrive control sets sensitivity and filter sweep rangeSelectable low pass, band pass or high pass filtersQ control sets the filter's bandwidth from smooth to funkyTough and compact die-cast chassis9-volt battery includedOptional 96DC-200BI power supply available