About: http://webisa.webdatacommons.org/208257935

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 layers of metal or metal alloy employed in the neutral density filters of the invention are generally of nickel, chromium, or alloys of these metals such as nichrome and chromel.
http://www.w3.org/ns/prov#wasQuotedFrom	google.com