Ancor heat-shrink connectors have heat-activated adhesive built into the sleeve of the tubing. When heated, these connectors form a watertight seal for the ultimate in vibration and strain relief. Tinned for corrosion resistance, the butt connectors feature pure copper for maximum current flow and a brazed seam for maximum strength. Provides the ultimate in vibration relief Pure copper for maximum current flow | Ancor 12-10 Heat-Shrink Butt Connector, 500-Pack