This effect is to modify the sound of your guitar, changing his personality, just like a Varitone.
Depending on the settings, the sound is gaining in emphasis, or it becomes thinner and teeth.
So there is a large volume pot (as "chicken" that I love Me) to choose among the 5 position, another (same form) to make up for lower volumes and a switch Snarl / Bite. This modifies the attack (soft / hard or growl / bite if you translate word for word) so it is 2x5 = 10 different sounds.
And there is a bypass mode for use as a clean boost pedal (never tried).

That is, it's all in my head because I sold the pedal since.
But today I decided to pay my debt to AF and capture views on the products I used or that I always use.

Ah yes, the hatch to the 9v battery is one of the simplest and easiest to use I've seen. A large screw that can loosen fastoche with any pick, remove the small plate, you change the battery, the plate and delivers one-hop a shot pick to screw, done.
The big dog's eyes glow red when you use the pedal, too nice.

UTILIZATION

It fastoche, there's only try all combinations and hold his little head in those suitable guitarist.

SOUND QUALITY

I say "those who agree" because I think only 2 or 3 positions suitable for each guitar.
I used this pedal with a guitar style Telecaster and indeed, all combinations were not adapted, some did not change anything in the end ...
There I believe this pedal should work better on a guitar with humbuckers to approach a single coil sound, rather than vice versa ...

Otherwise, this pedal is really quiet (as long as one does not push the volume knob to donf).

OVERALL OPINION

It's worth a try, but do not expect to use it in any position, it really depends on your guitar.