Hair extensions should only be applied by licensed professionals. Check with your local “State Board of Cosmetology” for more information. The “Hair Extension Training Guide for Professionals” is a resource for information only. Use at Your Own Risk. This information does not guarantee that you will be able to get or apply hair extensions properly. Rather, it gives you enough information to help you make better hair extension decisions. Professionals who are certified by sending a manikin to Vision Hair Extensions are only assessed on the quality of the application on the manikin received by Vision Hair Extensions. Vision Hair Extensions does not, and cannot, guarantee that the certified professional will apply hair extensions properly to clients.