Fire remains a real and constant threat to any building and that's why it's vital that all the necessary precautions are implemented. When you specify FlameBlok, you're installing a continuous ring of fire protection around openings in cavity walls. As the first fully test fire-rated cavity closer for cavities greater than 100mm and the only fire-rated closer manufactured entirely from post-consumer recycled UPVC, FlameBlok stands for the next generation in sustainable fire protection.