Under the pressure and flow conditions, AAK hydraulic valve effectively controls the sealing ring of each hydraulic valve, so it always ensures that the flow parameters in the hydraulic directional valve system are at the normal value. Only a small detail of the sealing ring has made the reputation of AAK hydraulic valve exceed that of many domestic and foreign peers. I will not modest about this. Many hydraulic valve manufacturers are used to domestic sales and are used to dogmatic production. Maybe they can copy the production process of their peers and continue to use some traditional technologies, but they may be helpless on the details or hidden problems of some spare parts. Leo, an old customer, suddenly sent me 3 samples of hydraulic directional valve some time ago. I didn't receive any email about these samples of hydraulic directional valve in advance. So I thought Leo asked us to offer a quotation. After receiving the hydraulic directional valve samples, I asked him by e-mail how many quantities he needs and what scenario this hydraulic directional valve will be used, then I would give him the plan of this hydraulic directional valve. However, Leo didn't need my quotation, just let me judge the quality of these hydraulic directional valves. Sending samples to let me just see the quality without doing other actions. This was the first time I had met. After testing these hydraulic directional valve samples, AAK HYDRAULIC VALVE technical team found the overall quality was good. The only hidden danger was that the flow parameters of one of the hydraulic directional valves were a little unstable, which should be adjustable in use. I directly told Leo that these hydraulic directional valves were qualified, but he should pay attention to flow adjustment during use. Leo's email reply surprised me again. Leo said that no wonder he stumbled in purchasing these hydraulic directional valves. Even AAK HYDRAULIC VALVE couldn't find problems with these hydraulic directional valves. I angrily asked the technical team to test these hydraulic directional valves again and simulate the use scenario of Leo's hydraulic directional valve under the pressurization and flow scenario. The test report came out soon. There were problems with the sealing rings of these hydraulic directional valves. Leo was relieved when he learned of the result and found the root of the problem. 30% of the hydraulic directional valves he purchased this time had the problem of flow parameters lower than the standard parameter values required by customers. His hydraulic valve manufacturer had been unable to find the root cause of the problem. He never thought it was caused by the mismatch of sealing rings. The traditional nitrile rubber sealing rings were not suitable for hydraulic scenes.