[99.9% Pure Tinned]- High-quality effectively prevents copper layer rust and then cause bad contact,anti oxidation prevent electrical . It provides minimal voltage drop, high current and less heat. These prevent short circuits and and make your connection projects and better. [Durability & Safety]- The polyolefin heat shrink tubing provides the high tensile strength and resistance to stretch and minimize mechanical damage, so there's no worry of rat chewing or similar physical damage issues. The thick tinned copper and seamless design ensures strong and secure crimping all the time with no issues of wire off. About this item: [Marine Grade Wire Connectors] - The heat shrink connectors kit includes ring, fork, spade, and heat shrink butt connectors. ( AWG22-18, 16-14, 12-10 for 3 types gauge, 3 colors&8 sizes ) The high-quality wire connectors make work easier. [Waterproof & Flame-retardant]- Insulation tubing features a dual-walled design. Adhesive lined inside the 3:1 heat shrink connector exude hot melt adhesive when evenly heated, shrinks quickly and adheres to wire insulation, which 360 degree secure seal and excellent waterproof property. Insulated waterproof marine grade crimp terminals can be used underground., Weight: 1.40985616549 Pounds, Manufacturer: NONDK