Capacitor assemblies. Can only be assembled inside the vacuum tube. The isolators are a tight fit to the connection rods. Special tool has to be designed to use to press the plates over de rods without damaging the housing or plates. Materials used are Gold (3+), copper (2+) and Silver (1+). The anticipated heat has to be redirected (thermal tubes) al used materials are excellent heat conductors but connection rod voltage is high (HV ~ 100kV) electric insulation required.