A pair of electric brushes from a universal motor of an electric drill (around 500 W). The width of each brush is around 10 mm. The contact surface is curved to conform to the radius of the commutator.
new_carbon_brushes_magnetica.jpg
You are permitted and indeed encouraged to use this image freely, for any legal purpose including commercial, and with any modifications (the permission is hereby given, so there is no need to ask for it explicitly again), but you MUST always give the following credits:
S. Zurek, Encyclopedia Magnetica, CC-BY-4.0
We would appreciate if you let us know of any use: info@e-magnetica.pl