Fotag 60pcs Waterproof Solder & Seal Heat Shrink Butt Connectors with Soldering Sleeve Wire Connector Terminals Electrical Copper Four Size Material: Tinned Copper Polyolefin tubing in outside and hot melt adhesive in inside Polyolefin heat shrink butt connectors improved pullout strength, provides seal, strain relief, cable check, and insulation An easy one step connection of wires, soldered, insulated and sealed Package include: 25Red 20Blue 10White 5Yellow