Here's how the guarantee works:

LEDriving headlights that fail to work properly as a result of a product defect in non-commercial applications during the several years period are covered by the OSRAM guarantee. Please note: The guarantee applies only to countries with customer service addresses.

To receive a replacement, please send the defective product in a protective package along with your cash register receipt and postage paid by the sender to the OSRAM contact address in your area and you get free replacement. In individual cases you receive a similar product or a credit note of the purchase price. Your statutory rights to non-defective goods remain unaffected.