About: http://webisa.webdatacommons.org/134836351

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 transmit warnings via audible and visible signals, such as alarms and flashing lights, when dangerous levels of gas vapors are detected.
http://www.w3.org/ns/prov#wasQuotedFrom	wikipedia.org