Using this spark plug wire set is straightforward. First, make sure your engine is off and cool. Match the numbered wires to the correct cylinders and connect them according to the color - coded coil wires. The positive - locking terminal ends will snap into place easily. When it comes to maintenance, keep an eye on the high - temp silicone outer jacket. If it gets dirty, you can clean it with a mild soap and water solution. Avoid using harsh chemicals as they may damage the jacket. Since these are clearance items and non - returnable, check the installation carefully to ensure everything is working properly right after you install them. Also, note that these wires are designed for 1991 - 1994 Nissan 4 - Cylinder Engines, so don't try to use them on other models without consulting a professional.