This V2 Custom Reverb Signature is an earlier Two-Rock amp, as you can see by the "K&M Analog Designs" and hand written signatures on the back of the chassis. Known for being used by guitarist John Mayer, this is the model that preceded the John Mayer Signature amp. During this era they were built in fairly limited quantity, and thus hard to come by on the used market. It’s in great condition, showing only minor signs of wear.
It should be noted the amp has a 60 cycle hum when used on the half power mode. This is likely a due to a minor design flaw, as early Two Rock amps are known to have.