Elevate your classic Buick Fullsize or Riviera with our top-of-the-line Backup Light Switch Extension Harness. Designed specifically for 1963 and 1964 models, this premium-quality harness ensures seamless connectivity from your dash harness to the transmission-mounted backup light switch. Engineered for 4-speed manual transmissions, our product guarantees reliable performance and enhanced safety, making it the perfect choice for restoring or maintaining your classic vehicle.