Rytons A1 Fire Rated Metal Rytweep Cavity Weep Vent - Box Of 50The Rytons Concealed Cavity Weep Hole Duct is a high quality, A1 fire rated metal solution designed to ensure free drainage within cavity walls. With its two part electroplated coating, this pre formed component offers excellent durability and is virtually invisible once installed, blending seamlessly into mortar joints. It is suitable for high rise buildings over 11 meters where people sleep and within 1 meter of external boundaries in England,