The 415V 16A 4-Pin Extension Lead Adaptor converts a 415 16A 4-Pin plug to a 230V IEC socket which allows testing on 415V 16A extension leads when used in conjunction with a 415V 16A 4-pin appliance adaptor. It is suitable for performing earth bond testing, insulation testing and polarity checking and is just 30cm in length which reduces resistance. It should never be connected to a mains socket.