hairpin clip
A hairpin clip, also known as a retaining pin,{{Citation | title = Pins | url = http://www.mcmaster.com/#hairpin-clips/=39f37f | accessdate = 2009-08-19}}. is a type of formed wire used on a grooved shaft. It is designed to be easily installed and uninstalled, and is reusable. They are commonly made from 1050 carbon steel and 300 series stainless steel.{{Citation | title = Hairpin clips | url = http://www.itwblh.com/hairclip.htm | accessdate = 2009-08-19 | url-status = dead | archiveurl = https://web.archive.org/web/20040807104903/http://itwblh.com/hairclip.htm | archivedate = 2004-08-07 }}.