1. National joint warranty means that you can go to any official after-sales repair point across the country for testing and warranty services with your invoice and warranty card. This means that the product can be provided with warranty service at its after-sales service center in mainland China based on the invoice.

2. The materials required for nationwide warranty are as follows: formal handwritten or machine-printed invoice, and warranty card. If not, you will not be able to get the after-sales warranty and other corresponding after-sales services. 3. Handwritten or machine-typed invoices are acceptable, but the prerequisite must be a formal invoice. It's the same if you have a joint guarantee card.