... 3,convinience 4,good quality 5,elegant apperance 1,The roller door,roller shutter door adopts new material of aluminum alloy, the double layer ... , durable and nice.Using specilized exterior motor with thermel protection device ,durable,low noise, easily to install. 4,The open command ... power failure also. 5,The opening speed of the roller door,roller shutter door can up to 0.1m/s,which save the power ...