Echelon's ASTRA-GLAZE-SW+® units are pre-faced architectural glazed concrete masonry blocks that have a thermoset glazing compound permanently molded to one or more faces. This glazing compound is cured and heat-treated in gas-fired tunnel kilns — thus becoming an integral part of the masonry unit. The glazed concrete masonry units are molded in individual molds, ensuring dimensional uniformity of the glazed facing regardless of minor variations in the block