Rings, hooks, spades, quick disconnects, and butt connectors are included in this multi application set. You will find the right connector for all of your electrical wiring projects Adhesive lined translucent heat shrink tubing provides high tensile strength, as well as resistance to weather, stretch and mechanical damage Thick barrel ensures strong crimp every time - your wire will never slip out of these connectors The color of the terminal insulation represents the size of wiring that fits the terminal; Red Connectors: 0.4mm to 1.5mm2 / 22-16AWG Wire, Blue Connectors: 1.5mm to 2.5mm2 / 16-14AWG Wire, Yellow Connectors: 4.0mm to 6.0mm2 / 12-10AWG Wire