Its a (pre)amp simulator pedal with full analog signal chain using JFETs instead of values and copy the Mesa Boogie Rectifier red channel.
Some people might recall I got an JCM800 based Amt M1 pedal a while back and was very underwhelmed. It was half the size and price of a Sansamp British, but sounded half as good. Anyway, it wasn't totally bad and I did use it for some things.
So recently I have been looking at modernising my sound a bit. 7 string guitars, detuning, and high gain amps are all things I have been checking out. Checking some Mesa Boogie rectifier tones out on youtube I came across a comparison against an Amt R1 pedal.
Anyway, it sounded surprisingly good, and was a gorgeous looking fire engine red colour. So I decided to take a punt.
The point is - it sounds rather good, much better than the M1 and more versatile too. Theres not much in the way of clean tone, but theres a good selection of higher gain sounds to be hand. It sounds better than my Sansamp GT2 set to California mode too.
Overall, I'm happy with the purchase, and it was affordable too.
I wouldn't say it 100% nails the Mesa sound, but it is a good sounding pedal.
Edit: I still think a high gain valve amp would be a good idea for me to own