Incredibly Rare Op Amp Distortion which uses the famed LM308 chip to get that original vintage mid-range distortion. The Hartman Electronics LM308 Op-Amp Distortion guitar pedal offers two modes of distortion inspired by the edgy, modern styles distortion popularized by punk, new-wave and college-rock bands of the late 70's and early 80's. The pedal it is based on goes for over £500! So this is an incredible deal for anyone into that style of music.

Never heard nicer, warmer feedback from any other pedal, this thing really sings!
Now a discontinued and rare pedal, its in great condition with just a couple of very small dints and velcro on the back. 

If you're more fuzz inclined, check out my listing of a Devi Ever/Dwarfcraft Sliver ROse v2 (hailed as "The Ultimate Fuzz" by many)...

By the same company as the Hartman Analog Flanger (said by many to be the best clone of the legendary very original Electric Mistress), Hartman are known for making high quality clones using only the best components, and even improving on the vintage designs to make them more user friendly for the modern.

In the case of their LM308 op amp, they took the exact circuit of the highly sought after original big-box Pro-Co Rat and added a switch to complete alter the character of the pedal:

Distortion mode (A) employs a diode-clipping stage to produce a classic distortion and crunch of the original upon which it is based, exhibiting the same sensitivity to player pick-attack, palm-muting- and pinch-harmonics.The second distortion mode (SYM) transforms the pedal into an overdrive, increasing transparency, headroom, and dynamic response, and producing a hotter output signal suitable for overdriving the input of downstream amps/devices. Your strat sounds like a strat, your LP sounds like an LP; no more masking the tone of your instrument, but still plenty of scream, crunch, and sustain. Features:9vdc 2.1mm external power jack (center -)Foot-switchable distortion mode selectorDual LED indication (On/off & Mode)Metal-can type LM308AH Op-AmpLow noise 1% carbon-film resistorsHeavy duty true-bypass switching