About: http://webisa.webdatacommons.org/188552378

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	However, it can be difficult to manufacture relatively large tubes that are made of materials such as Nitinol, and these tubes can therefore be expensive and difficult to find.
http://www.w3.org/ns/prov#wasQuotedFrom	freepatentsonline.com