About: http://webisa.webdatacommons.org/218387213

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	The spring wires or stiffeners can be made of any suitable resilient material but are preferably formed of a material such as a spring steel having a stiffness equal to or greater than that of the flaps.
http://www.w3.org/ns/prov#wasQuotedFrom	google.com