An adapter includes: a power input terminal for connecting an AC power supply; a power circuit that performs energy conversion on the inputted AC power to obtain electrical energy capable of powering a power tool; and a tool interface connected to a power interface of the power tool to output electrical energy. The adapter further includes a data transmission module connected to at least the tool interface and capable of outputting first communication data and/or first internal resistance data to the tool interface so that the power tool is capable of identifying the adapter according to the first communication data and/or the first internal resistance data. The first communication data includes at least adapter identification data, and the adapter identification data enables the power tool to identify that a connected device is the adapter between the adapter and a battery pack.

A gas pressure driving device includes a first driving shaft that drives a driven body in a first direction by a pressure of a gas, and a second driving shaft that drives the driven body in a second direction intersecting with first direction by the pressure of the gas. The first driving shaft drives the driven body in the first direction by the gas supplied through an inside of the first driving shaft and the second driving shaft.

A gas pressure driving device includes a first driving shaft that drives a driven body in a first direction by a pressure of a gas, and a second driving shaft that drives the driven body in a second direction intersecting with first direction by the pressure of the gas. The first driving shaft drives the driven body in the first direction by the gas supplied through an inside of the first driving shaft and the second driving shaft.