StreetWires designed the SPD4 spade connectors to attach to your 4-gauge power wire, for a more secure connection to power cable inputs. They provide a more professional-looking installation than bare wire, and prevent corrosion of the copper strands in your cable by protecting them from exposure.
Crimp the connectors onto your wires and slide the included PVC boots up to protect the connection. One pair per package. Warranty: lifetime.