About: http://webisa.webdatacommons.org/231842479

Property	Value
http://www.w3.org/1999/02/22-rdf-syntax-ns#type	http://www.w3.org/ns/prov#Entity
http://www.w3.org/ns/prov#value	may be formed from various materials such as cork or polyvinyl chloride foam fashioned as a flexible friction material.
http://www.w3.org/ns/prov#wasQuotedFrom	google.com