The ideal bulbs for professionals who travel off-road, or make special demands on light power. Such as those in agriculture or forestry, or on building sites. In addition, Hella light has been involved in many victories in 24-hour races. Note: Please note that due to high voltage can generate overheating in the wiring of the headlight.When it comes to driving safety, sight is the most important sense. Visibility can be impaired under various circumstances and driving under these adverse conditions will increase the risk of an accident. To meet these challenges, HELLA is continually improving existing lighting systems and developing new lighting equipment and components. HELLA bulbs undergo strenuous quality tests. This is achieved by using the most modern equipment in light metering, which provides information if a bulb has the necessary properties.Hella products are subjected to the following tests:Geometric Measurement: A measuring projector is used to check the filament geometry - with regard to the statutory standards in accordance with IE C 60810. The filament must be dimensionedand positioned within the bulb as specified in the standard. This is the only way to achieve optimum headlight power and prevent glare to oncoming traffic. Life Test: Sophisticated tests are used to prove the high reliability of the HELL A bulbs over a long period. Vibration and Shock Test: Here, vibration resistance of the bulb and the filament in particular, is tested on an electrodynamic vibration table.Paint Adhesion Test: The adhesion of paint on colored glass bulbs such as the PY 21W for example is tested in a climate chamber at different temperatures and air humidities. Optimum adhesion of glass bulb paint guarantees the prescribed amber indicator light over the whole service life period.