●Package Includes: 100Pcs yellow heat shrink butt connectors for 12 to 10 AWG wire. ●Tinned Copper Core: Waterproof butt connectors use a heavy-duty copper core, strong crimp, higher conductivity. ●Waterproof Durable: Insert the wires to be connected, crimp both sides with crimping pliers, and then heat with a heat gun, butt connectors very strong. ●3:1 Shrink Ratio: Marine grade wire butt connectors provide high tensile strength and enough hot melt adhesive inside the tubing to ensure waterproof performance, your wires will never slip out of the wire connectors. ●Wide Application: Waterproof butt connectors are durable, stable, waterproof, and corrosion resistant and are used in the automotive, marine, electrical, and electronic industries.