If the ’90s had an official mascot besides flannel shirts and questionable hair dye, it would be the Electro-Harmonix Big Muff fuzz pedal. Born in the late ’60s, the Big Muff was designed to take a guitar tone and politely destroy it. By the time Grunge stormed out of Seattle’s rain-soaked basements, the pedal had already become the secret weapon for turning angst into amplified chaos.

Nirvana’s Kurt Cobain is often remembered for using distortion pedals like the Boss DS-1, but it was the Big Muff that many of his contemporaries swore by. Soundgarden’s Kim Thayil wielded one to sculpt massive walls of sound, and Mudhoney’s Mark Arm practically baptized the pedal into the grunge church with their 1988 EP Superfuzz Bigmuff—the title wasn’t subtle. The pedal’s ability to turn a simple riff into a fuzzy landslide fit perfectly with the genre’s mix of punk attitude and Sabbath-style sludge.

Technically, the Big Muff works by clipping your guitar’s signal into a square wave, but in practice it feels more like feeding your amp a steady diet of coffee grounds and rage. Its sustain knob could make a note hang around longer than the awkward silence after you tell someone you “still listen to CDs.”

So while Grunge may have faded from mainstream charts, the Big Muff endures. It’s still humming away on pedalboards worldwide, proving that sometimes the best way to express yourself is to stomp on a box that makes your guitar sound like it’s been chewing gravel since 1991.