It equipped exterior or between twin glass.The C shaped shutter produced by aluminum-alloy cold rolled.It enhance the wind-resistant function with 6 level wind power. 80mm aluminum-alloy shutter is equip with guiding device of steel wire and siding track device. The guiding device is simple,reliable and steady. The function of wind-resistance and steady mechanism of the siding track is better than steel guiding device.It is more suitable for place needing more wind-resistance. You can control in the way of manual or motor no matter where you are in the room.