[Transparent Sleeve] Transparent sleeve of the wire connectors provide visual inspection [Well Performance] Polyolefin tubing provides insulation and improve pullout strength. Waterproof and perfect sealed can protect electrical connections [Easy to Use] Just simply put the stripped wires into the solder wire connect and apply heat to finish the connection [Wide Application] Widely used for marine , home wiring, DIY electrical repairs and etc [Warning] Please keep it away from children under 3 for the small parts may cause choking hazard