I believe it's the widebody. To my knowledge, Mesa only offered the smaller sized combo with the Nomad 45. The rest of the line (Nomad 55 & 100) came in widebody 1-12" versions.
It's great when I show up at a jam, and everyone looks at each other when they see my little amp. The same question is always answered..... "Yeah, the little amp can keep up with the drummer".