[Easy to Use] No crimping required! Simply insert the stripped wire into the solder connector, then heat it evenly to complete the connection. Shrinkage Ratio: 2:1. It can work without special tools (such as crimping pliers). [280pcs Wire Connectors] Included. 100 red (0.5-1mm2), 100 blue (1.5-2.5mm2), 60 white (0.25-0.34mm2), 20 yellow (4-6mm2). Dual-walled design: polyolefin tube outside, hot melt adhesive inside. Provides precise control of internal ribbons and inserted wires. Allows visual inspection to prevent corrosion and form a watertight seal. [Safe and Efficient] The waterproof heat shrink connector series is made of environmentally friendly and flame-retardant insulated heat shrink tubing, providing high tensile strength, waterproof and leak-proof. Improves contraction strength, ensures insulation retention, strain relief, and cable control. [Wide Range of Applications] 280 butt connectors are available in 4 different sizes, which are used in the automotive, railway, naval