ZOOM A1X FOUR Acoustic Multi-Effects ProcessorWith specially engineered effects processor, built in looper and drum machine, the A1X FOUR is the first Multi Effects Processor designed for a variety of acoustic string and wind instruments. 'X' is for additional Xpression. The A1X FOUR effects processor comes with 8 additional pedal controlled effects to adjust volume, pitch, reverb, delay, and wah. A1X FOUR effects processor offers over 80 built in effects A1X FOUR offers over 90 built in effects.