Dual Direction < Input 110/120V to Output 220/240V> Or <220/240V to 110/120V
You need to check the switchs place at the bottom of the adapter(Black Swith Back )
That is:Switch to AC117Vinput voltage must be AC110/120Vvoltage converter (output) AC220/240
Switch to AC230Vinput voltage must be AC220/240VAnd change the voltage into (output) AC110/120V.
Attention:it will be broken with wrong operationand we will not responsible for the wrong operation.