Have used this in many studio sessions, and it really shines. Such an incredible piece of vintage gear.

Borrowing description from someone else with a great wording:

Vintage EHX Graphic-Fuzz pedal unit in excellent condition. It has distortion, an envelope filter, and a graphic EQ. The switch allows you to use the pedal as a graphic EQ or just the fuzz. The envelope is basically like setting a wah in a specific position. It produces an exceptionally wide range of sounds and textures that change dramatically with playing dynamics. It uses an envelope follower that responds directly to pick attack, causing the EQ and fuzz behavior to change dynamically depending on how hard or softly the strings are struck.

This is a line-powered unit - the power supply is built in. 
There are a few scratches and blemishes which are clearly visible in the photos.