Keeley Compressor PlusThe Keeley Compressor Plus is a compressor with an expander sustainer. Not only does it act as a regular compressor, limiting the peaks in your playing, it adds more and more gain as notes fade out. Now you have sustain. Nothing worse than a note or a bend that has died before its time. The Keeley Compressor Plus adds just the right amount of sustain and expressive bloom to your notes. Excellent condition, includes box. Power: 9VDC, ultra low current