Very rare hard to find adapters for rims with slightly different bolt patterns. These can be used to upgrade your Chevy Volt rims from 2011/2015 to the newer volt rims 2016/2022! You can use these on several GMC vehicles and Chevy ETC...any company under GM. You should of course verify whether they fit first, and yes they have to be an exact fit otherwise you will get vibration in the wheel. These also extend your wheels out about an inch without causing any rubbing issues. These are brand new never used from a machine shop in California...you can purchase them straight from the company on eBay for $89 a piece...or you can buy mine for much cheaper! Half price $45 a piece hoping to sell as a set for $80 locally, shipping will include shipping and tax unfortunately.