According to the FMVSS 205, Every Auto Glass Part, Both Original Equipment and Aftermarket have to display visible markings to assure that the glass part complies with Safety Standards and this is called a “Monogram” or otherwise known as a “BUG”.   Every Manufacturer has a different Bug.  The Bug will display the following information: Brand Name or Logo which can either indicate the manufacturer who was responsible for manufacturing the glass part for the vehicle manufacturer or it can display the vehicle manufacturer itself.  To add an additional twist to it just because the logo is stamped on the glass doesn’t necessarily mean that this company actually produced the part, They could just be the company that contracted the part to be made.

DOT # This number is the number used to identify the actual producer of the part.  DOT stands for The Federal Department of Transportation.  The DOT issues a unique license # to all glass fabricators or manufacturers that produce auto glass partss in accordance to the FMVSS 205 and ANSI Z26.1.  The DOT # is the only identifier of the true producer of the given auto glass part.   A contractor can allow a glass fabricator or manufacturer to use their name or logo but they are not allowed to use their DOT number.  To check the DOT

The “M” symbol is the actual glass manufacturers unique identification number for one particular individual glass part.  This # will provide information pertaining to the part such as configuration, color, thickness of the glass, laminate, coatings, frit configuration and attachments associated with the part.  Every manufacturer has their own set of “M” numbers so none of them are they same.   Every company utilizes “M”  as their part identification except for Ford who uses “FM” go figure!

AS stands for “American National Standard for Safety Glazing Materials for Glazing Motor Vehicles and Motor Vehicle Equipment Operating on Land Highways-Safety Code”  or  the actual summarized definition “American Standard”.   AS-1 is can be used on all auto glass applications.  Windshields with Sunshades are excluded due to the privacy tinting and this exception can be noticed by the symbol used in the upper top of corners of the glass that will indicate the lower glass part is AS-1 but the upper part where the sunshade is is in fact not AS-1.  AS-2 is used on all auto glass except the windshield.  AS-2 is usually tempered glass for example the drivers side and passenger side front and rear windows.  AS-3 is for Privacy Glass or otherwise also known as tinted glass.  The main difference between these 3 designations is AS-1 has passed a light transmittance and penetration test.  AS-2 has only passed the light transmittance test.  AS-3 doesn’t pass the light transmittance test or the penetration test.

Most Glass manufacturers will include the point of origin to identify where the part was made.  This is not required by law but most will do it anyway.  You may notice additional information listed on the glass and this information typically is unique to the manufacturer and may include information such as the manufacturing plant info, date, plant and batch codes.  All of this really is just to ensure your safety and that there is a set safety standard in place to protect people from poor manufacturing processes.  Without these codes and information it would be a safety disaster and know one could or would be held accountable for poor quality glass and companies taking shortcuts.

European Standards with the Monagram/Bug Symbol/Stamp

Europe has a uniform standard that is universal and the stamp can be Identified with an E.  Directly above the “E” will rest the “type of glass” symbol.




Joseph Newsome