Polycarbonate is a versatile, tough plastic used for a variety of applications, from bulletproof windows to compact disks (CDs). The main advantage of this material over other types of plastic is its great strength combined with light weight. While acrylic is 17% stronger than glass, polycarbonate is nearly unbreakable. Bulletproof windows and enclosures as seen inside banks or at drive-throughs are often made of this plastic. Add to this the advantage that it is just 1/3 the weight of acrylic, or 1/6 as heavy as glass, and the only drawback is that it is more expensive than either.