You can complete the connection faster and easier than the previous method. The wires can be tightly secured and connected. Polyolefin and hot melt provide waterproof protection and prevent wire damage. Not only can it protect electric wires but also reduce . Features - ColorAssorted Color - Material: Plastic and tin ring. - Size: 4.00X0.80X0.80cm/1.57X0.31X0.31in - Transparent heat shrink sleeve allows for precise visual inspection. - used in electronics,railway, marine, automobile, motorcycle, aerospace and other outdoor applications. - Connectors are placed in a box for easy storage and portability. - Different colors can easily help customers identify connectors. - The hot-melt solder and adhesive inside tubing that the wires are tightly connected to prevent them from slipping out of the wire connection. Package list: White Solder Heat Shrink Sleeve 70 x Red Solder Heat Shrink Sleeve 60 x Blue Solder Heat Shrink Sleeve 20 x Yellow Solder Heat Shrink Sleeve 420 x Black Heat Shrink Sleeve