Assertion: bowling ball's urethane coverstock | /r/HasProperty | the end of the rubber ball era
Facets:
value: entirely
type: DEGREE
Source sentences:
text: The low friction surface coverstock on a rubber ball actually produces slightly more surface friction than does polyester (plastic) bowling balls and is similar to the low grade original urethane coverstocks but not as versatile as urethane material coverstocks, thus the end of the rubber ball era entirely.