All Raider helmets are approved by a Department of Transportation standard, which establishes a minimum performance requirement for helmets designed for use by motorcyclists and other motor vehicle users. (Federal Motor Vehicle Safety Standard 218 - also commonly known as the DOT helmet standard.) All helmets sold in the United States that are intended for motorcycling must meet this standard.
The purpose of this standard is to reduce deaths and injuries to motorcyclists and other motor vehicle users resulting from head impacts. In order to do this, helmets must go through a series of impact testing, involving various faces of a helmet experiencing a sudden stop on a hard, heavy surface. The results are analyzed, and those that pass receive a DOT sticker at the back of the helmet. All Raider helmets receive this sticker.
For more information on Federal Motor Vehicle Safety Standard 218, you can find it in it's entirety in PDF form here.