Proton with PBI was specially developed for the Polish market. Developed and produced in Poland it´s a further addition to the global PBI outer shell range. Brochure Where to Buy WHY CHOOSE PROTON? Meets and exceeds the Polish norm PN EN-1149-5. High abrasion resistance and tensile strength. Proton does not shrink, become brittle or break open under exposure to extreme heat and flame.