The MXR Blue Box became the go-to octave effect and a gear icon after Jimmy Page used it for his solo in "Fool In The Rain." It's incredibly simple - two knobs for Output and Blend - one of those pedals that just does its thing and sounds good without a ton of dialing in. It tracks your notes and doubles with a two-octave down copy, providing a bassy, raw feel. Put it front of a fuzz and stand back.
At some point in this pedal's life, it was modded with a bright switch located on the left side of the pedal.
This classic blue pedal is lightly used and will ship safely and swiftly! Give us a shout at the shop if you have any questions about this pedal.