DDN devotes to the objective : Offering top products and top service to our customers.
         Our quality undertakings are:
         1. Implement the “three quality guarantees” system of contracting for returning, changing and repairing.
Company ensures to returning or changing and repairing freely for our products which has any its quality problem found in using within one year. 
         2. Carry out lifetime service system for all our products.
For all our products, Company is responsible for tracing its quality problems and after-sale servicing from putting it in use to be discarded as useless. When quality guarantee expire, Company will collect cost for repairing and parts changed, only. 
         3. We are always servicing where there are our products.
After receiving user’s report about quality problem of the Company’s products, we will replay within 24 hours and arrive at the spot within 48 hours for domestic users required urgent service.