With the patent no. of ZI200420114206, D25 elevator system mainly uses D25 motor as power driver. Hence, the elevator system and direction changing system can work respectively. Each string is corresponding to its rolling part, on the rolling part through obverse and reverse spirals to prevent string twist and to keep the same direction and velocity during operation. This product is suitable for interior shutter blinds, symphony blinds, and pleated blinds. Handle bar control, motorized control and radio remote control are available. Packing: one piece one package