The best fitment for the centre cylinder on Laverda 3 Cylinder models 1000/120/RGS.

For the two outside cylinders use 73202031.1 Spark Plug Cap NGK XB05F 8062 Black

Featuring a resistor element pressed in between the plug terminal and the high tension wire connection, the construction is extremely durable, the resistor element is long enough to prevent interior flashover, and steady resistance is maintained. Superlative ceramic materials are incorporated that resist deterioration and have small resistance variation under over-load, whilst the plug connector is made of sturdy phenolic resin, practically oblivious to tremendous heat and high tension, and very rugged rubber material. The heat press insertion makes the construction all the more tough and vibration-resistant. Special rubber liners on both ends prevent moisture from causing electrical leakage.

Due to the harsh operating environment of the resistor caps, the rubber seals preventing moisture from causing flashover can deteriorate.  Regular inspection of the resistor cap in recommended and replace when there is any sign of physical damage or wear.