Cavity Weep Vent 100 x 65mm is used when water needs to be drained from an external wall. It is suitable for using at ground floor slab level, with cavity tray systems and over external lintels. The vent can be used with brick, block and stone and helps to ventilate cavity walls. The baffled grill stops rain and wind entering the vent and prevents blockages from foliage and debris.