The Easy-Twist WWC-GR-B-NL 500-Count Bag of Green Winged Wire Connectors are designed for grounding copper wires in the 14-12 AWG size range. They have a hole in the top designed for a through-wire and are made of flame-retardant thermoplastic. The quick-grip square spring design grips in fewer twists and can dead-end a single wire, while the ergonomic swept-back wing design and ribbed texture makes them easy to twist. Their compact design is useful for applications in tight areas or anywhere else you need to connect wires.