About: http://webisa.webdatacommons.org/211530028

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 piston 18 is made of metal, glass, ceramic materials or plastics such as polyethylene or PTFE. Materials transparent for infrared or other forms of electromagnetic radiation can also be used.
http://www.w3.org/ns/prov#wasQuotedFrom	google.com