My periodic table poster is now available! Zirconium oxide street luge bearing. This is a solid zirconium oxide ceramic ball bearing meant for street luge, whatever that is. See similar silicon nitride ball bearing. Source: eBay seller irvineman Contributor: Theodore Gray Acquired: 24 March, 2009 Text Updated: 25 March, 2009 Price: $30 Size: 0.75" Composition: ZrO2