Quality control(QC) is a process that is used to ensure a certain level of quality in a product or service. 
 

Zhengdian company have a professional QC team who focus on testing led writing board and observing services for more than 8 years. Our led advertising board are chosen and examined at random. The goal of our quality control team is to identify products that do not meet ourcompany's and consumers' specified standards of quality. 
 

Believe us, believe Zhengdian, dependable, satisfactory, safe and fiscally sound products will be provided!