This is an automatic translation of the original german program description, made by Google's translation service:
Volumouse them to the volume of the PC using the mouse wheel (wheel to scroll) of their computer mouse to steer. So they can always quickly adjust the volume without looking for the volume control of Windows to have.
To avoid conflicts with the scroll function of this key, they can set additional parameters (bsw. only change volume when in addition the Alt key is pressed). Thus Volumouse always available, they should start the box "Enable Volumouse with Windows."