Gardner Bender Wire Connectors are engineered to exceed the expectations of professional electricians. Perfect for commercial or residential applications GB Wire Connectors offer world-class quality, performance and application versatility. The industry's standard twist-on connector with quality performance and durability. GB specifies this connector for a wide range of 22 - 16 AWG and recommends a wire combination of Minimum: (3) 22 wire and Maximum: (3) 16. It is blue in color for easy color code identification. Recommended for copper to copper connections only. Made from tough, thermoplastic shells which guard against hydrocarbons, diluted acid or alkaline solutions.