TwinStomp is a UK-based boutique pedal company founded in 2006 by father-and-son team Clive and Adam. The company launched its first product, the TwinStomp Booster, in 2007, which went on to win Best Effects Pedal 2008 from Guitar & Bass Magazine. Every pedal is hand-built and hand-soldered by the founders, with each unit taking approximately four hours to complete.

TwinStomp's product line includes the Booster (a dual MOSFET clean boost, now in its MkIII revision), the S21 Overdrive (a dual-channel overdrive that has become the company's best-selling pedal), the OD-Boost (combining overdrive and boost circuits that can be cascaded for high gain), and the Active A/B-Y MkII signal splitter. All pedals are housed in proprietary investment-cast stainless steel enclosures weighing just over 1 kg each — a distinctive departure from the stamped aluminum boxes used by most manufacturers. Adam holds a UK patent for the brand's battery release mechanism, designed for quick battery changes.

The S21 Overdrive has been praised by publications including Guitarist, Total Guitar, and Guitar & Bass Magazine, with Guitarist calling it "every bit as 'boutique' as anything else out there in terms of tone and build." The pedals are primarily aimed at blues and classic rock players looking for transparent, amp-like overdrive tones.