The Easy-Twist WWC-Y-J1 500-Count Large Jar of Yellow Winged Wire Connectors are designed for use on copper wires in the 18-10 AWG size range. They???re made of flame-retardant thermoplastic rated for a maximum temperature of 105?? Celsius (221?? Fahrenheit). 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. Manufacture Part Number: WWC-Y-J1 UPC - 662381201034 Sold as a pack of 500 Units. Standard List Price each is $0.2105