BSM is a German boutique effects manufacturer specializing in handcrafted treble boosters and related guitar pedals. Founded by Bernd C. Meiser — the initials reference Bernd and his wife Steffi Meiser — the company grew out of Meiser's work as a writer for the German magazine Gitarre & Bass, where he documented the history of vintage stompboxes. Readers who wanted clones of the classic circuits he covered prompted him to start building pedals commercially, beginning around 2003.

The catalog centers on recreations and variations of iconic treble boosters such as the Dallas Rangemaster and Hornby Skewes, built using period-correct parts like OC44 germanium transistors. Notable models include the BM-Q (inspired by Brian May's Queen-era tone), the Black Box Booster (based on Angus Young's studio techniques), the Starbreaker Booster (a tube power amp simulator), the Spectrum Fuzz Booster, and the Galaxy 1011. The range extends across low-, medium-, and high-gain boosters, tone-controlled boosters, fuzzes, overdrives, and loopers, all hand-built to order rather than produced from stock.

The brand is closely associated with the treble-boosted amplifier tones of late-1960s and 1970s British rock, and its "ToneZone" documentation references the rigs of players including Ritchie Blackmore, Brian May, Eric Clapton, David Gilmour, and Keith Richards.

BSM has 26 products cataloged on Equipboard, including Boost Effects Pedals, Fuzz Effects Pedals, and Switch Effects Pedals. Their gear is featured by 3 artists, with the strongest followings in Rock. Notable users include Noel Gallagher, Billy Gibbons, and Emmanuel Éthier.