We provide one year guarantee service for all the item sold. The date is counting from 7 days after invoice shipping date. If you found defective units within one month after you get the goods, please take picture and descripe the problem of the item, we will give you replacement, and you do not need to send back. If it is more than one month, we need your help to send back the units with any cheap way like EMS or something, we will give you free replacement with shipping charge on our side.