1)Aluminum Alloy 2)low voice 3)needn't setting limit 4)intelligent control and stop-on-resistance 5) ... control is available,alsocan be connected with multimedia central control system, realize programmed control and remote control,realize more sets of single control ... . 7.With function of stop-on-resistance ,protect the whole system,safety running. 8.Both electronic control and handing pulling,hand ...