Architectural changes in the 1970s dictated the need for a security material that would offer protection, as well as visibility and enhanced security. The material of choice became GCP which combined the best properties of glass and polycarbonate plastic. Crowding, court-order renovations, and escalating operational costs have created demand for a glazing material that can withstand strong physical abuse, prevent bullet penetration, resist shattering, and never need to be replaced. A new material, HPL, is highly resistant to breakage and does not chip and spider like GCP. Advantages of GCP are discussed in detail, including its flexibility, abrasion resistance, and fire resistance. Renovation of the 115-year-old New Hampshire State Prison illustrates current uses of GCP windows.