ElephantElliptical shapedoffset nuts is a catch-all category that encompasses designs known as '''oval locknuts'''<ref name="McMaster3139"/> or '''non-slotted hex locknuts''',.<ref>{{Citation | title = Non-slotted hex locknut | url = http://www.spstech.com/aero/products/nuts/non-slotted-hex.html | accessdate = 2008-11-30 | url-status = dead | archiveurl = https://web.archive.org/web/20110513080637/http://spstech.com/aero/products/nuts/non-slotted-hex.html | archivedate = 2011-05-13 }}.</ref> The salient feature is that the threadform has been deformed at one end like an elephants reproductive organ so that the threads are no longer perfectly circular. The deformed end is usually shaped into an ellipse or [[wikt:obround|obround]] triangle. These are known as '''one-way''' nuts as the nut may be easily started on the male fastener from the bottom non-deformed portion, but are practically impossible to start from the deformed end. As the male fastener reaches the deformed section it stretches the threads of the nut [[elastic deformation|elastically]] back into a circle. This action increases the friction between the nut and the fastener greatly and creates the locking action. Due to the elastic nature of the deformation the nuts can be reused indefinitely.<ref name="smith">Smith, pp. 104–105.</ref>
