I purchased this at a vintage instrument store in Tokyo. I'm selling it because I no longer use it. The switch is a little loose, so sometimes the on/off switching isn't quick. I've only used it a few times in the studio and for home recording, and have been storing it since. Below is a quote from the shop's description when I purchased this item: "This is a black label 1982 TS9 serial number 222187, using the JRC4558D op-amp, which can be said to be the pinnacle of the TS9. The Ibanez Tube Screamer has become one of the representative models of overdrive/booster pedals, so much so that the term "TS-type" can be used in the descriptions of various effects pedals today. The first model, the TS808, was released in 1979, and Stevie Ray Vaughan used the TS808 and TS9 in the early 1980s, and his blues played with exquisite Strat tones gained worldwide recognition. Following this, the Tube Screamer, combined with various amps and guitars by SRV followers, created a genre of overdrive pedals. Various types of op-amps have been used in the TS808 and TS9, which are the key to the sound. Among them, the "JRC4558D" used in this unit is the most popular and the tone that many people imagine with the Tube Screamer. It creates an exquisite sound characterized by moderate fineness, a beautiful high-end, and a unique mid-range that brings out the best of Fender-type amps. This unit shows signs of considerable use from its appearance, and some solder repairs can be seen, but it maintains its original condition. Compared to the later models from 1983 onwards, the sound is creamier and softer, while still having good note separation. The plain strings have a solid core, and the overtones are exquisitely mixed, creating an exquisite tone. When used as a booster with the TONE set to 3 o'clock or later, just like SRV, you can truly enjoy the Texas blues sound with this exceptional unit." Please refrain from purchasing if you are looking for a perfect product due to its age. Please consider this item with a full understanding that it is a vintage instrument.