The appearance design of the door leaf is concealed, and the door leaf and the surrounding walls are integrated. The extremely narrow frame (2mm) and high-quality finishes (paint-free board, wood veneer, rock board, etc.) highlight the most essential beauty of product materials. The door body structure has a sealing system, and the door core is filled with aviation aluminum honeycomb. The sound insulation can reach 25db. The overall door thermal conductivity K ≦ 2.0w/(m2k), has excellent sound insulation and heat preservation.