Common Options

In the Tool Settings you can select the brush and material to use with the tool.

The データブロックメニュー to select a preset brush type or a custom brush. See Brush options.

Data-block selector for the material. Except for the Erase tool of course.

Pin Material (pin icon)

Pin the material to the brush.

The final appearance of the strokes is a combination of the brush and material used, binding the material to the brush gives more control and avoids a lack of coordination between the two.