Oyviny 4-Way Flat Trailer Wiring Harness — 10.5 ft Coiled Extension, PU-Jacketed Pure Copper

The Oyviny 4-way flat trailer wiring harness is a stretchable 10.5-foot coiled extension with color-coded pure copper conductors protected by a durable PU jacket for reliable taillight and signal connections.

This compact, coiled trailer cable is engineered to replace worn or broken 4-way flat plugs and to extend trailer wiring without loose cables dragging on the road. The 10.5-foot design stretches and contracts to give extra reach while the polyurethane (PU) jacket improves abrasion and weather resistance compared with standard PVC sleeving. Color coding and a standard male flat plug make splicing and installation straightforward for common boat, ATV, motorcycle, and utility trailers.

How long is the cable and how does the coiled design help?

The harness measures 10.5 feet fully extended (126 inches) with a typical working length around 9.5 feet when under mild tension. The coiled shape keeps excess cable compact when not stretched, preventing dragging and tangling during turns or when backing up. This also reduces wear on the wires and improves safety by keeping the cable off the ground.

• Nominal full length: 10.5 ft (126 in)
• Typical working length: ~9.5 ft (114 in)
• Coiled form minimizes slack and abrasion
• Stretchability provides flexible towing distance

Can I install this harness on my existing 4-way flat connector?

Yes — the Oyviny extension uses the standard 4-way flat male plug compatible with most vehicle 4-way flat sockets. Color-coded internal wires let you splice into existing trailer wiring quickly to restore taillights, turn signals, and brake lights. The plug is sized for common trailer applications, so replacement or extension is a simple retrofit.

• Standard 4-way flat male plug fits industry sockets
• Color-coded wires for easy identification and splicing
• Compatible with most boat and utility trailers
• Works for taillights, brake lights, and turn signals

What materials and construction protect the wiring?

The cable uses pure copper conductors for efficient current flow and reliable signal transfer. A polyurethane (PU) outer jacket covers the wires, offering improved temperature tolerance and abrasion resistance compared with traditional PVC. These choices extend service life in harsh outdoor conditions and reduce the chance of wire exposure or breakage.

• Pure copper cores for stable electrical conductivity
• PU jacket resists wear, sunlight, and temperature changes
• Weather-resistant construction for outdoor use
• Color-coded insulation maintains clear wiring identification

What trailers and situations is this harness best suited for?

This 4-pin coiled extension is ideal for small to medium trailers where a standard 4-way flat connection is used. It’s particularly handy for boat trailers, ATV haulers, motorcycle trailers, and utility trailers that need a bit more reach without permanent cable slack. The compact coil also helps when trailers are frequently coupled and uncoupled or when storage space is limited.

• Boat, ATV, motorcycle, and light utility trailers
• Replacement of worn or damaged 4-way plugs
• Situations needing flexible, non-dragging wiring
• Frequent connect/disconnect trailer use

Who is this for: The Oyviny 4-way flat coiled trailer wiring harness is designed for DIYers, boat owners, tow operators, and small-fleet managers who need a reliable, stretchable 4-pin extension. If you want a compact cable that stretches when necessary, resists weather and abrasion, and plugs into standard 4-way sockets for easy splicing and replacement, this harness delivers a practical and durable solution without complex installation.