Flea relies on his main Modulus bass for the majority of the set. It's outfitted with a Modulus Lane Poor pickup, which is no longer in production, an Aguilar preamp, and a Leo Quan Badass bridge. He keeps his knobs taped at his preferred settings (bass almost full up, treble rolled off) and only uses his volume knob live. The Modulus has a graphite neck that allows Robar to set Flea's action very low and Flea uses his signature set of GHS Boomers (.105 - .145).
In addition, he uses (left to right) a Modulus bass with custom Aboriginal finish and a Seymour Duncan pickup that's tuned to Drop D for "By The Way," a Modulus bass with the Aboriginal national flag with the controls built into a cavity on the back (only an on/off switch on the face) tuned down a half-step for "Breaking the Girl," a Chinese-made Flea Bass with custom Damien Hirst spin-art finish, his main Modulus, a backup Damien Hirst-painted Flea Bass, and a Fender P-Bass that isn't used live. Far left is a Fender Bass VI used by Josh Klinghoffer on "Happiness Loves Company" while Flea plays piano. In the gig bag is a five-string Modulus used for "Funky Monks."
Flea uses three Gallien-Krueger 2001RB amps, one controls the other two as slaves. The amps run into three Gallien-Krueger 410 cabinets and three 115 cabs, all running. There are two additional 2001RB amps in the rack, one is used when Klinghoffer plays bass, and the other is simply a backup.
Flea doesn't use many effects, relying on these four for all of the tones he needs. Left-to-right he uses a Malekko Bassmaster for fuzz and distortion, MXR Micro Amp used as clean boost for slapping and leads, Electro-Harmonix Q-Tron used for "Sir Psycho Sexy," and a Moog Mooferfooger 12-Stage Phaser used just for fun. The board is powered by a Voodoo Lab Pedal Power 2 Plus.
Click here for a photo gallery with more detailed pictures of Flea and Josh's touring gear.