About: http://webisa.webdatacommons.org/134243915

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	Materials having a density below that of the heavy metals, such as lead, are preferred in order to provide the required mass characteristics.
http://www.w3.org/ns/prov#wasQuotedFrom	patentgenius.com