Easy-Twist Winged Twist-On Wire Connectors - Winged Yellow Carton 18-10 AWG- 550 Count APPLICATIONS: Easy-Twist Winged Twist-On Wire Connectors have deep surface ridges to provide better grip. Ergonomic, swept-back wing design provides handling comfort and increased torque ability. Flame retardant UL 94V-2 thermoplastic shell provides excellent electrical insulation. Fixed, precise square wire spring provides secure gripping of conductors. Deep skirt entry provides protection from flashover and shorts. Compact design ensures proper installation, especially in tight spaces. Threaded funnel entry guides the wires into the connector easily. Pre-twisting of wires is not necessary. Zinc-plated springs for low contact resistance. UL 486C Listed Wire Connector. For Copper Wire Only.