Mayones Caledonius 5 Custom | Petrol Spill

The Mayones Caledonius is one of the most distinctive boutique basses ever built — and this one pushes it into true one-off territory. Finished in a custom Petrol Spill matte, the top shifts like an oil slick under light, moving between blue, pink, purple, and violet tones over a hand-selected Curly Poplar 3A top. It’s bold, elegant, and unmistakably modern, especially paired with the sculpted Caledonius body and integrated access handle.

Under the hood, this build is all performance. A neck-thru construction with a 9-ply Maple/Mahogany neck and Birdseye Maple 3A fretboard gives you that signature Mayones feel: fast, rigid, and incredibly resonant with piano-like sustain. The 20” radius and 24 FERD WAGNER nickel-silver frets make it effortless to navigate, while the 34.25” scale keeps tension tight and consistent across the fretboard.

Electronics are handled by the next-gen VELVETRONE / Musashi Nitōryū 3 system with push/pull active/passive, full EQ control, and a dedicated PassiveTone — meaning it can go from vintage warmth to modern hi-fi grind without ever losing clarity. Dual VELVETRONE Noble 5 soapbar pickups make sure every note stays focused and articulate, sitting perfectly in a dense mix or stepping forward for solo work.

Rounding it out is a hardware set designed for real-world use: an X25 two-piece bridge with 19mm spacing, HIPSHOT Ultralite tuners, ebony nut, SCHALLER security locks, and multiple connection options including USB-C, AUX, and headphone outs for modern practice and stage setups.

Handmade in Poland, loaded with premium tonewoods, and finished in a colour scheme you’re unlikely to ever see again, this Petrol Spill Caledonius is a legitimate one-off for players and collectors who want something that blends artistry with serious studio- and stage-ready performance.