Vintage DOD Preamp Pedal. This is one amazing sounding boost/preamp. These were made during the time DOD was making the original grey 250. This is a simple FET preamp- plug it in and adjust volume to taste. This has a TON of output, so start slowly. This adds a beautiful thickening to everything in your chain that is just very robust, yet also very musical. Kills the boost pedals of today. These are highly sought after by people in the know.