Twist-on wire connector (Marrette) High temperature marrette #35. Rated 105 degree C - 600 Volts. Wire range: 18-8. Black. Connect and insulate 2 or more bare copper wires. Each wire connector is constructed of durable flame-retardant material to help provide long-lasting use. Twist-on wire connectors are a type of electrical connector used to fasten two or more low-voltage electrical conductors