Keeley Stahlhammer distortion. This is the 'british stack in a box' offering from Keeley. It's voiced to respond like a Marshall JCM800: heaps of harmonics and midrange crunch. There's two modes, switchable via the little switch on the side: crunch and lead mode. The difference is the amount of compression and gain on tap; the lead mode offers some very saturated tones indeed. If you need some enormous thick saucy British gain in your life, look no further.

Model: Keeley Stahlhammer Distortion
Made in: USA, 2015 (serial D0247)
Type: British mid-high gain distortion
Power: standard 9v supply or battery
Equivalent new street price (approx): $240
Mods: none
Accessories: original box and manual included
Condition notes: neglible scratches and and marks; excellent condition

Here's a handy demo  to give you the idea.