Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Bullet-resistant glass is a type of strong but optically transparent material that is particularly resistant to being penetrated when struck by bullets. It is also known as transparent armour. Bullet-resistant glass is usually constructed using polycarbonate thermoplastic or layers of laminated glass. The aim is to make a material with the appearance and clarity of standard glass but with effective protection from small arms fire. Polycarbonate designs usually consist of products such as Armormax, Makroclear, Cyrolon, Lexan or Tuffak, which are often sandwiched between layers of regular glass. The plastic in laminate designs provides resistance to impact from physical assault from hammers, axes, clubs, and so forth. The plastic provides little in the way of bullet-resistance. The glass, which is much harder than plastic, flattens the bullet, which prevents penetration. This type of bullet-resistant glass is usually 70-75 millimetres thick.