PREMIUM MATERIALS - AIRIC heat shrink butt connectors have the high-quality copper tubular, which ensures increased current flow, and less voltage drop, thus preventing wiring failures and reducing equipment downtime. Also, the thick tubular of butt connectors ensures strong crimp every time - your wire will never slip out of the connector | DURABILITY - Translucent heat shrink tubing provides high tensile strength and resistance to stretch and mechanical damage. Dual-walled tubing ensures waterproof seal and prevents wire corrosion. The inner wall of waterproof heat shrink tube has enough hot melt adhesive to ensure waterproof performance | WATERPROOF - Designed with polyolefin outside and hot melt inside provides excellent waterproof property. When heating, the polyolefin tubing reduces in size and adhesive flows inside the insulation. The butt connectors heat shrink comply with all relevant standards, Shrinking ratio: 3:1 | EASY TO USE - Strip wire insulation and insert into shrink butt connectors, crimp the connector tubular, and heat with a hot air gun or small torch. Just a few seconds. No soldering kit required. REMEMBER: The red butt connector should be used for 22-16 AWG, blue butt connector for 16-14 AWG, and yellow butt connector for 12-10 AWG | QUANTITY - 200pcs blue 16-14 AWG heat shrink butt connectors. As its great waterproof and conductivity, AIRIC heat shrink butt connectors are ideal used for marine, automotive, home, or scientific projects.