1. 30mm optimum length set spring with mute;
2. Patent buffer effectively protect the pull beam and accessories;
3. The double-faced cleaning device;
3. the second generation strong windproof system.;
4.the transverse beam. Pull the following installation of a pulley, reduces the screen
switch when the pull beam positioning card and rail friction;
2. Patent buffer effectively protect the pull beam and accessories;
3. The double-faced cleaning device;
3. the second generation strong windproof system.;
4.the transverse beam. Pull the following installation of a pulley, reduces the screen
switch when the pull beam positioning card and rail friction;