The DFR22 is a rock-solid two-channel DSP with many drag-and-drop processing features. The only drawback is the serial programming interface. (Shure recommends the FTDI US232R USB to RS232 adapter and it works great!)
This item was used but it works just like a new one. The only drawback with a DFR22 is having to use RS232 to program it but that was common when this was designed.