"Type of filament lamp" means filament lamps that do not differ in such essential respects as:
1.1.1. the trade name or mark;
1.1.2. the nominal voltage;
1.1.3. the nominal wattage;
1.1.4. the shape of one or more filaments;
1.1.5. the colour of the glass envelope;
1.1.6. the design of the glass envelope and its effect on the optical results.
