Assertion: ballpoint pen's ball | /r/MadeOf | steel
Facets:
Source sentences:
text: Ball at the point can be of different diameter and can be made of brass, steel, or tungsten carbide.
text: A ballpoint pen is a pen that uses a small rotating ball made of brass, steel or tungsten carbide to disperse ink as you write.
text: A ball point pen is a pen that uses a small rotating ball made of brass, steel, or tungsten carbide to disperse ink as you write.