Metal Zone MT-2 electric guitar distortion pedal by Boss.
Yes, the infamous distortion pedal that gets a bad reputation because of it's improper use. Whilst it's usually easy to get a "jar full of bees" sound from this I have done the Diezel mod, replacing/removing specific capacitors and LED's to remove the harsh "nasal" sound and making the EQ much more usable and noticeable.
This pedal is obviously best used for metal in most of its forms, especially black metal. It's recommended to keep most of the dials at 12 o'clock though some people may benefit from the more harsh distortion obtained by higher gain, giving the classic "Swedish black metal buzzsaw" sound.
I'd recommend renting this pedal so you can experience it yourself first before you commit to buy one elsewhere or if you need it for a gig. The metal case is sturdy so is ideal for stage use.