Cobra 909-TWINS 4" SLIP-ONS BLACK FLSB 18-22 - 2018-2025 — Harley-Davidson Softail Fat Boy 114, Softail Fat Boy (2018-2022)

Cobra 909-twins 4" slip-on mufflers in black for 2018-2022 Harley-Davidson Fat Boy S (FLSB), delivering classic Harley tone through a 2.25" perforated core with a stealth-style downward angle tip design. Made in the USA and 50-state street legal.

Features

• 4" twin muffler ends with downward angle profile
• Scalloped twin tips with no visible external screws
• 2.25" perforated core for traditional Harley sound
• Black finish
• 50-state street legal
• Limited lifetime warranty
• Made in the USA

Specifications

• Brand: Cobra
• Manufacturer Part #: 6520B
• Length: 33.5 in
• Width: 8 in
• Height: 5.25 in
• Weight: 11.68 lbs

Fitment

Fits 2018-2022 Harley-Davidson Fat Boy S (FLSB) models.

Frequently Asked Questions

Do these require a tune or ECU flash?

Slip-ons alone typically do not require remapping. A fuel tune may optimize performance if running with other modifications.

Are they street legal?

Yes — 50-state street legal and EPA compliant.

What sound can I expect?

The 2.25" perforated core delivers a classic, recognizable Harley tone — not overly aggressive.

Is installation difficult?

These bolt directly onto stock head pipes in place of factory mufflers. Basic mechanical skills and hand tools are typically sufficient.