OEM stands for Original Equipment Manufacture. This means that the auto glass meets the original specification for safety and quality as the glass that it came with from the factory. Auto manufacturers do not make glass. They use different auto glass manufacturers’ to make the glass for your vehicle. A “dealer” glass is the same glass the auto glass shop would have, made from the same auto glass plant, but, in the process, the auto glass manufacturer stamps the brand name, such as Toyota, or Ford, making it a “dealer.” Same exact glass, but more expensive due to the brand name.
OEM auto glass means it is essentially the same piece of glass that is installed at the time the vehicle is made with the only difference being the windshield manufacturer. OEM glass is produced from original equipment-style tooling and meets the manufacturer’s specification for safety and quality. Only OEM glass can insure proper fit and finish which greatly reduces the possibility of air or water leaks. Most importantly, only OEM glass is designed specifically to meet the safety standards necessary for protection in an accident. You should always use OEM glass to insure your safety. If you are making an insurance claim to pay for your windshield replacement, you are mostly entitled to OEM glass. You have paid for it in your policy.
There is plenty of cheap non-OEM quality after glass market out there, but saving a few dollars on a piece of glass that may or may not fit right or be of the right thickness is not worth the risk to car owners.
OEM suppliers are trusted by auto manufacturers like GM, Chrysler, Toyota, Ford, etc to provide quality controlled windshields that are a perfect match and fit for their vehicles. OEM suppliers spent hundreds of million dollars in research and development, using computer-assisted engineering and designs programs (CAE and CAD) to ensure quality windshields for their vehicles.
Each OEM windshield goes through rigorous and thorough surface contour and optical quality checks as it moves down the assembly line. Auto glass parts produced by OEM manufacturers consistently fit better and adhere to the same standards for fit and finish as the glass that is originally installed when the car is built.
The after market shops will tell you that their product is the same quality as an OEM windshield. Wrong. Non-OEM auto glass manufacturers make copies of OEM auto glass parts. These copies have to vary slightly from the OEM part due to the fact that OEM parts are patented and the designs are protected and trademarked.