... Good quality & nice packing 2. Small MOQ & competitive price 3. Copper slip ring 4.Constant tension cable reel ... ,when the the drum roll the cable,the motor of the cable drum is charged with electricity, ... the cable is released,at this time,the motor of cable drum stop working and skid institutions begin ... side,then cable is released,at this time,the motor of cable drum go on working,skid institutions ...