Adapter and power tool system

A power tool system, comprising:

• a single-voltage battery pack having a single-voltage output interface, the single-voltage battery pack configured to output only one kind of voltage;
• a first power tool having a single-voltage input interface being coupleable with the single-voltage output interface of the single-voltage battery pack;
• a dual voltage battery pack having a dual voltage output interface, the dual voltage battery pack configured to output two different kinds of voltages;
• a second power tool having a dual voltage input interface being coupleable with the dual voltage output interface of the dual voltage battery pack;
• and
• an adapter comprising:
• an input port being coupleable with the single-voltage output interface of the single-voltage battery pack or the dual voltage output interface of the dual voltage battery pack;
• an output port electrically connected with the input port and being coupleable with the single-voltage input interface of the first power tool or the dual voltage input interface of the second power tool;
• a switching mechanism being switchable between a first state and a second state;
• a housing for accommodating the input port, the output port and the switching mechanism;
• wherein when the input port is coupled with the single-voltage output interface of the single-voltage battery pack and the switching mechanism is in the first state, the second power tool is coupled to the output port and powered by the single-voltage battery pack, and when the input port is coupled with the dual voltage output interface of the dual voltage battery pack and the switching mechanism is in the second state, the first power tool is coupled to the output port and powered by the dual voltage battery pack.