This Regulation applies to motor vehicle headlamps which may incorporate lenses of glass or plastic material. 1. DEFINITIONS For the purpose of this Regulation, 1.1. "Lens" means the outermost component of the headlamp (unit) which transmits light through the illuminating surface; 1.2. "Coating" means any product or products applied in one or more layers to the outer face of a lens; 1.3. "Headlamps of different types" are headlamps which differ in such essential respects as: 1.3.1. the trade name or mark; 1.3.2. the characteristics of the optical system; 1.3.3. the inclusion or elimination of components capable of altering the optical effects by reflection, refraction, absorption and/or deformation during operation. However, the fitting or elimination of filters designed solely to change the colour of the beam and not its light distribution shall not constitute a change in the type; 1.3.4. suitability for right-hand or left-hand traffic or for both traffic systems; 1.3.5. the kind of beam produced (passing beam, driving beam or both); 1.3.6. the holder intended to accommodate the filament lamp (or lamps) of one of the categories H1, H2, H3, HB3, HB4, H7, H8, H9, HIR1, HIR2 and/or H11; 2/ 3/ 1.3.7. the materials constituting the lenses and coating, if any. 2. APPLICATION FOR APPROVAL OF A HEADLAMP 4/