1.       The frame adopts 1.2mm high quality cold-rolled steel plate, door leaf is inflaming retarding plywood or high strength paint-free board. The frame is flaming retardant wood.

2.       Door leaf is filled new environmental inflaming retarding and insulating material, shaping by environment adhesive press. After deoil, derusting, phosphorization and passivation,the surface is spray-paint and heat thermal transfer.