12 Rounds is Claudia Sarne (vocals, keyboards, pianos, string bass), and Atticus Ross (drum/instrument programming, samples, bass guitar). They are joined by a rotating cast of live drummers, cellists, chainsawists, etc. They have also collaborated with Barry Adamson, Nick Cave, Keith Hildebrant, Clint Mansell, and others, and are published (in the US) on Trent Reznor's nothing records.

The music of 12 Rounds is very diverse. Songs next to one another on the disc will often have near opposite styles. One could be punk or hardcore in mood, and the next, a twisted nursery rhyme, complete with "sing song" melody, and music box pianos.

They have two albums:
Jitter Juice
My Big Hero (which is basically the refined version of Juice Juice and was released in the USA).