The BSM RM is based on the british Range Master unit produced between 1965 and 1969, as used by Eric Clapton in John Mayall's Bluesbreakers. Eric also used the booster when playing in the legendary group Cream. Its biting, powerful sound is clearly in evidence on the Bluesbreakers "Beano" album. Blues rocker Rory Gallagher, Glam rocker Mark Bolan, Heavy Rock pioneer Tony Iommi and Brian May from Queen were also heavy users of the original Range Master unit.