3M™ Constant Force Springs, for Solderness Connections. 

3M™ Constant Force Spring is a solderless connection, making it ideal for use on lead and aluminium cable sheaths, cable screening tapes or wires and steel or aluminium armor wires.

• 3M™ Constant Force Spring is designed for earthing or grounding applications. The spring applies a uniform radial pressure onto the cable when it is rolled onto the cable core or outside diameter.
• Applies a uniform radial pressure onto the cable
• For use in earthing or grounding applications
• Used on lead and aluminium cable sheaths, cable screening tapes or wires and steel or aluminium armour wires
• Solderless connection