Glass Thickness - The federal government actually has mandates on the thickness of a windshield. Most windshields are between 2-3mm (millimeters) thick. OEE glass may have a.01mm or more difference in thickness. This may result in the idea that aftermarket is more cheap. Although this is still as safe and equivalent to OEM, I find it is different none the less and may have a higher risk of cracking from debris impacts.