PREMIUM MATERIAL: High-quality tinned copper makes the butt connectors have strong conductivity and stable performance. In addition, the outer tube is made of polyolefin, which is heat-shrinkable and insulating. EASY TO USE: Insert the stripped wire into the butt connectors, use tool to crimp the of the butt connectors, then heat with hot until the tube is firmly attached to the wire. The operation is simple and the great shrink ratio (3:1) makes a good weather seal. WIDE APPLICATIONS: The heat shrink butt connectors can be widely used in marine, boat, automotive, etc. In addition, the butt connectors are waterproof and solid to meet your circuit connection needs. DURABILITY AND CONVENIENCE: Translucent tube enables you to observe the connection condition and improve efficiency. The use of heat shrink butt connectors is convenient, good material ensures the safety and prolongs the service life. WHAT YOU GET: 70PCS Red 22-16AWG, 80PCS Blue 16-14AWG, 40PCS Yellow 12-10AWG, 50PCS White 26-24AWG. Colour:As Shown Material:copper Package Contents: 1 set x Heat Shrink Connectors Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.