The factory seatbelts in the 1990-2000 Nizzan 300ZX were a dual retractor design. As the belts age, the retractors can become problematic and often times stop functioning all together. Our single retractor conversion kit updates your seatbelts to a more reliable and modern design that ensures years of reliable service. No modification is needed as the belts are a direct-fit, bolt-in replacement. If you need help with installation we are happy to help!