Assertion: bass drum's head | /r/MadeOf | plastic
Facets:
value: usually
type: DEGREE
Source sentences:
text: The heads may be made of calf skin or plastic and there is normally a means of adjusting the tension either by threaded taps or by strings.
text: The beater head is usually made of either felt, wood, plastic, or rubber and is attached to a rod-shaped metal shaft.