Auto Glass Facts Knoxville's Finest Auto Glass Installation Center Auto Glass comes from a variety of different manufacturers and different degrees of quality. The information below will help you sort out the difference.  Every part of a new car comes from an Original Equipment Manufacturer (OEM), including the windshield.  The only two  automobile companies that actually make their own glass are Ford and Chrysler.  For windshield replacement, you have two  options.  Your first option is to select a replacement made by one of the many companies that manufacture OEM windshields,  such as PPG, Ford Carlite, LOF/Pilkington, Guardian, etc. Your second option would be to select a Windshield made from non-  OEM manufacturers called "Aftermarket Glass".  Both OEM and Aftermarket auto glass must comply with the same Federal  Motor Vehicle Safety Standards.  There are two important OEM benefits:  An OEM replacement windshield is produced from original equipment tooling.  This type of windshield will have the appearance  of your car's original windshield and will fit properly in the window opening making noise, leakage, as well as cosmetic  problems, much less likely.  OEM auto glass manufacturers work hand in hand with automobile manufacturers to enhance  overall functionality and improved performance.  Because of their close work with auto manufacturers, OEM manufacturers  have a greater knowledge and understanding of the engineering demands that the vehicle can place on the windshield in both  normal and crash conditions and their replacement windshields are made using the same quality assurance systems they use  for the original vehicle manufacturer.  Safety glass is used in all auto glass. It is manufactured to reduce the likelihood of personal injury when and if it should break.  There  are two different types which are called laminated and tempered glass.  Windshields as well as  some side and rear windows are made from a lamination process.  This type of glass actually  consists of two pieces of glass, bonded together by a "PVB" (polyvinyl butyrate) vinyl layer in  between the two layers of glass.  In the event of an accident  this vinyl layer serves several purposes, it cushions your head during impact, helps keep the  vehicles occupants contained within the vehicle  and also helps keep many small light weight  foreign objects from entering the passenger compartment.  If a windshield breaks, during  impact, the majority of broken pieces will generally adhere to the plastic lining.  Tempered Glass The majority of side and rear windows manufactured consist  of tempered glass which is produced with a process that  involves heating the glass to more than 1,100°F and then  rapidly cooling it.  This results in the outside surfaces of the  glass becoming harder than the center of glass which makes  it stronger than regular annealed glass of the same  thickness.  If broken, tempered glass will break up into very  small pieces which are less likely to cause as serious of an  injury as annealed glass would.