The SOS20 ’Breaker’ pack contains 40 captures of the Marshall Blues Breaker in each of the ToneX, NAM Standard and NAM Nano formats. (Full details above.)
 
Here's what Marshall say about their pedal: 
 
'The sound of the 1962 ‘Bluesbreaker’ amplifier became a legend, with the smooth tone, rich warmth and full character that gave guitarists more expression than ever before. The original Bluesbreaker pedal took this and put it in a stompbox.  It captures the magic of those classic vintage amps with added sweetness, crispness and extra edge to carry solos and squeeze out those vital harmonics.'
 
Treaded on by the likes of John Mayer, Chris Buck, Mick Ronson and Steve Cradock.