From the Joyetech website regarding warranty and serial numbers
An important role for warranty — Serial Number
In order to protect legitimate rights of users, Joyetech has pasted package serial number label on all the package boxes of Joyetech eRoll and eVic starter kits since September 2012, and then applied for all the other Joyetech products successively.
Users can check the authenticity of these products on the following website:
Joyetech Support. If the product is original, our system will show you the relevant package serial number. Meanwhile, the serial number and security code are also required for products warranty and after-sales service.
Detailed requirements are as follows:
1. If the package box for Joyetech eRoll or eVic has no serial number pasted, the product may be counterfeit, or those Not for Sell, such as test samples. Joyetech couldn't provide warranty and after-sales service without verification of serial number and security code. Please reject or return it to the supplier for the starter kits without such label.
2, From June 1st, 2013, if the serial number and security code can’t be provided, Joyetech will no longer directly support the after-sales service and warranty.
Sincerely please take good care of the receipt, serial number and security code for the product you bought.