Guangzhou Casen Door CO.,LTD strictly selects the raw materials of wooden door-soundproof door. We constantly check and screen all incoming raw materials by implementing an Incoming Quality Control - IQC. We take varies measurements to check against collected data. Once failed, we will send the defective or substandard raw materials back to suppliers.. We receive important feedback on how our existing customers' experience Casen brand by conducting customer surveys through regular evaluation. The survey aims to give us information on how customers value the performance of our brand. The survey is distributed biannually, and the result is compared with earlier results to identify positive or negative trends of the brand.. In order to deliver satisfactory service at Casen wooden door, we have employees who really listen to what our customers have to say and we maintain a dialogue with our customers and take note of their needs. We also work with customer surveys, taking into consideration the feedback we receive..