California Code of Regulations
Title 13 - Motor Vehicles
Division 2 - Department of the California Highway Patrol
Chapter 2 - Lighting Equipment
Article 2 - Identification Markings
Section 633 - Lens Markings

Markings on the exterior lenses of lamps and reflex reflective devices and photoelectric detectors and on exterior filters or transparent covers shall be visible from the outside when the device is installed. When removal of the lens from the housing would destroy the device, either the housing or the lens may be marked if the markings differ from those previously used on any similar device.

Note: Authority cited: Section 26103, Vehicle Code. Reference: Sections 24006 and 26103, Vehicle Code.