Time saver: no need to solder or crimp wires, the butt connectors terminals allow you to connect wires by using a heat gun, quickly and simply to finish the connection 5 Colors: the package contains 70 pieces red waterproof wire connectors, 60 pieces blue wire connectors, 20 pieces yellow wire connectors, 50 pieces white wire connectors, 400 pieces black wire connectors, 600 pieces in total, various colors provide convenience to identify Waterproof and airtight: each electrical wire terminal comes with 2 hot melt waterproof adhesive rings, helping to hold up to moisture, prevent wires from corrosion and avoid shrink tubing melting before soldering ring Convenient and safe to use: transparent sleeve allows to strip and insert wires inside more precisely, the adhesive would fill gaps within the terminal after heated, ensures a tight connection and avoids wire slipping out of the connector; Insulated design saves you from worry of electric leakage Wide application: the insulated butt splices are useful tools for marine, automobile, motorcycle and so on, provide a good protection to wires; Small items, please keep children away from them 600 Pieces solder seal wire connectors self-solder heat shrink butt connector waterproof insulated electrical butt splice wire terminals for marine automotive aircraft boat truck stereo wire joint Give wires a good protection: The solder seal splice is characterized by watertightness, corrosion prevention and insulation, helps to get rid of electric accident. Specification: Material: PVC Color: red, blue, yellow, white, black Operating temperature range: Operating temperature: -55C to 125C (-67F to 256F) Minimum shrink temperature: 80C (176F) Minimum temperature for solder to melt: 138C (280.4F) Size: Red connector: approx. 2.7 mm in diameter, cable cross-section 0.5 to 1.0 mm Blue connector: approx. 4.5 mm in diameter, cable cross-section 1.5-2.5 mm White connector: approx. 1.7 mm in diameter, cable cross-section 0.25-0.34 mm Yellow connector: approx. 6.0 mm in diameter, cable cross-section 4.0-6.0 mm Black connector: approx. 4 mm and 20 mm in length How to use: 1. Strip the 2 wires that going to connect and select the right size of connector. 2. Thread the connector to one of the wires and then twist the 2 conductors together. 3. Move the connector to the middle of the conductor. 4. Apply heat to the connector slowly and evenly with a hot air gun with nozzle until it melt with the wire. Package includes: 70 x Red connector 60 x Blue connector 50 x White connector 20 x Yellow connector 400 x Black connector Note: There may be small deviations due to manual measurement. It's recommend that use a heat gun with nozzle to heat the connector. Please rotate the wire when you are heating or surround the wire to heat so that the tube was heated evenly. It's recommend to keep 3 to 5 cm/ 1.18 to 1.96 inch between the nozzle to the connectors.