Mercedes R129 Seat Belt Outlet Kit – Black

This is a precision-engineered replacement kit for the seat belt outlet guides on the Mercedes-Benz R129 SL-Class. The factory seat belt outlet — OEM parts A1299100539 and A1299100639 — is a high-friction component that takes constant punishment from the seat belt webbing cycling through it daily. Factory units crack at the edges, scratch heavily, and eventually snap, leaving an unsightly broken trim piece at one of the most visible points in the R129 interior. We re-engineered this critical component to eliminate that failure permanently.

✅ AVAILABLE AS DRIVER'S SIDE (LEFT) OR PASSENGER'S SIDE (RIGHT): Order the side you need individually. Replaces OEM A1299100539 and A1299100639 directly.

The Engineering Edge

• ASA Construction: Moulded from engineering-grade ASA — inherently scratch-resistant and UV-stable. Unlike the factory material, ASA resists the continuous friction of seat belt webbing without developing the deep scratches and surface deterioration that make factory units look worn within a year.
• Exact OEM Geometry: Every mounting tab, belt channel dimension, and clip position is reverse-engineered from the original part. The guide installs in the factory location and routes the seat belt with the correct geometry and tension.
• Complete 3-Piece Kit: Each side includes all three components required for a complete outlet guide restoration — no hunting for individual pieces, no mismatched parts.