Flea's bass strings: the Red Hot Chili Peppers signature rig, sourced

Flea (Michael Peter Balzary) is the founding bassist of Red Hot Chili Peppers, the Los Angeles funk-rock band he co-founded with Anthony Kiedis, Hillel Slovak, and Jack Irons in 1983. Across the band's catalog from The Red Hot Chili Peppers (1984) through Return of the Dream Canteen (2022), Flea's hybrid slap-and-fingerstyle bass voice is the harmonic and rhythmic center of one of the highest-grossing rock acts in history. Rock and Roll Hall of Fame inductee 2012, Grammy winner across multiple albums, and a continuous GHS Strings endorsement artist with a production signature pack.

GHS Bass Boomers Flea Signature M3045-F (.045, .065, .085, .105). Nickel-plated steel roundwound on hex steel core, long-scale, the Boomers signature SKU built around his exact gauge specification.

His current signature bass is the Fender Flea Jazz Bass in Road Worn Shell Pink. His historical signature was the Modulus Flea Bass with a carbon-fiber neck, the bass that defined his Stadium Arcadium era tone. Modulus folded in 2014; Fender now carries his signature.

A Jazz Bass with the Boomers M3045-F medium gauge is the canonical funk-rock bass voicing: bright but not piercing, harmonically rich on the slap snap, mid-range punch that locks into the kick and snare without fighting Anthony Kiedis's vocal pocket. Flea's technique alternates slap thumb on bass-heavy passages with fingerstyle plucking on melodic counter-lines; the single set carries both registers without a string change between songs.

The .045 to .105 gauge is the working medium standard for slap-funk technique. Lighter sets (.040 to .095) lose snap on the pull; heavier sets (.050 to .110) lose articulation under fingerstyle. The Boomers gauge profile sits exactly where Flea's hybrid technique needs it.