The center is aluminum hexagonal honeycomb with low density (about 3-7kg per square meter), which is 1 / 5 of the weight of the same thickness and area wood, 1 / 6 of the glass and 1 / 7 of the aluminum, greatly reducing the building load and cost. Due to a large amount of air in the middle interlayer, it can be used for sound insulation (air sound insulation can reach 30dB), heat insulation (thermal resistance can reach 0.02 (M2 · K / W)), no combustible material, and the fire rating can reach B1 Waterproof, moisture-proof, no harmful gas release