CND Shellac is a professional product only and shouldn't be bought without any training and should be purchased from Authorised Distributors only.
Buying of EBay isn't wise for many reasons and esspessially if you are not trainined in the product.
And looking at your profile you are not trained in Nails therefore would need to gain a manicure qualification to purchase and use CND Shellac.
You have no idea if the product your buying is genuine which could result in you having a reaction. You would have no help if something went wrong which you would have from an Autherised Distributor.
I would strongly recommend you don't touch eBay when considering buying products designed for the professional market.
You won't find any professional on this site willing to give you any links for buying off eBay only links for training and Autherised distributors.
Not only would you not know if what you were getting off ebay was the real deal you would not know how to use it properly, also you need the CND lamp. To top off all of this off you would be paying more than you would professionally!!
If you want to use a Professional product as it was intended to be used then go to the authorised distributors