Genuine Nissan SR20DET Non-VVT Injector Seal Kit designed for the fuel injectors on Nissan Silvia S13 models equipped with a redtop straight cam non-VVT SR20DET engine. This kit is composed of four pieces of part number 16635-53J0A, four pieces of part number 16636-53J00, four pieces of part number 16618-53J00 and four pieces of part number 16618-10V05. The part number 16635-53J0A is the fuel rail insulator, which acts as a thermal barrier between the engine and fuel rail, helping to prevent heat transfer and maintaining fuel temperature. The part number 16636-53J00 is the injector insulator, which insulates the injector from the heat generated by the engine, preventing fuel from vaporizing and ensuring consistent fuel delivery. The part number 16618-53J00 is the injector o-ring, which provides a secure seal between the injector and the fuel rail, preventing fuel leaks. The part number 16618-10V05 is the lower o-ring, which helps to seal the injector to the intake manifold and prevent vacuum leaks.