Hope it is OK to post this, he is using a PRS guitar.
PRS does not offer a small battery operated amp.
This was a hot weekend in my state, and I had my portable air-con running most of the time, so it was too noisy to play guitar inside.
I played them on my porch this weekend sitting in a chair, and jamming to my iPod running through a Creative speaker which sounded good, but alas no amp for the guitar.
Thinking about picking up one of these Rolands when they hit the market.
There are several videos out of this amp including Paul from Guitar World, and a few others.
I have a Pignose amp, but it is to clean sounding for my taste, as I like a very dirty high gain sound.