1)Easy cleaning for their frame wth good connection. 2)Less air consumption with double door frame. The inner frame is close to the door curtain and the rubber bottom has the best sealing charactar. 3)Less bacteria growth for the best sealing solution without brush in the frame. 4)More durable due to the stainless frame material especially for pharmacy , food industry. 5)More softer inner frame ensures less-wear. 6)Controlling box with the screen-display.