Egg crate grille is made from aluminum extrusions having a crimped and welded frames with aluminum egg crate core. They are commonly used for return air, exhaust air or natural ventilation applications. Standard sizes: 150mm, 200mm, 250mm, 300mm, 400mm, 450mm, 595mmx595mm face. Customized sizes are also available upon request. Standard color: natural anodize or powder coated white.