About: http://webisa.webdatacommons.org/60544992

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	They may preferably be made from a rigid and hard-wearing material, such as, e.g., a plastics material or any suitable metal including aluminium and steel and their alloys.
http://www.w3.org/ns/prov#wasQuotedFrom	google.com