About: http://webisa.webdatacommons.org/123117423

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	Assuming a frequency of 20 kHz and material such as aluminum, steel or titanium, a half wavelength resonator is about 51/4 inch (134 mm) long.
http://www.w3.org/ns/prov#wasQuotedFrom	google.co.uk