Procture structure,torque nut.to insure the puncture pressure,and it 's easy to fix. Procture structure,torque nut.to insure the puncture pressure,and it’s easy to fix. pressurized structure,corrosion protection,and have a longevity of service contact resistance is small,and the temperature of cord grip is low.It’s connected with different pathway lead.and it’s useful.insulating propertry is ...