4/0 or 2/0 XL Wire Ferrules With Heat Shrink - Copper Available in 10, 25 or 100 pack. Variety of Heat Shrink colors to choose from. Ensure reliable electrical connections and prevent fraying or breaking your wire strands when terminating conductors in screw clamp terminal blocks. Their shorter lengths and uninsulated bodies offer advantages when making terminations in narrow widths. Uninsulated ferrules prevent wire strands from fraying and breaking and are extremely cost effective. To ensure efficient ferrule crimping, always select the smallest ferrule diameter that fits the wire and use only professional crimping tools.