You can view and edit the properties for a sculpt tool as follows:
The Properties window displays all properties for the selected sculpt tool.
The Size and Strength properties control the radius of the tool cursor and how much influence it has when pushing or pulling vertices on the surface of a model.
The Falloff property controls how the effect of the tool diminishes from the center of the tool cursor towards its outer edge(The circular outline indicates the region of falloff). You can quickly modify the brush falloff by selecting a Falloff preset from the Falloff tray or by editing the shape of the falloff graph in the Falloff section of the tool properties.