The real McCoy! The SR-71 Blackbird™ “Tube Tone Engine” is a full-featured vacuum tube preamp, in a pedal. Designed for tone & versatility, the SR-71 will add clean/drive/distortion channels to vintage/boutique guitar amps, or work as a stand-alone direct recording tube preamplifier. The clean channel possesses a beautifully pure, “glassy” character, and the drive channel is tuned to deliver a rich, full-bodied, devastatingly smooth overdrive. I purchased this unit to give my Peavey Chorus 212 a tube sound. It has been in the box since then. So it is basically been on one time since it was purchased. Ended up getting a koch Juniper so I'm selling this pedal and my Peavey Chorus. The cheapest one I found was on e-bay at $709 plus tax. So I feel this is a fair price to be asking