One German customer required us to change the design of rubber gasket, our technical team thought that it was not 

necessary to change, since if change, the mould had to be changed and that would cost a lot of money, and the performance 

after changing was not better. But the customer insisted and he would bear the cost.

Our technical engineer made the changes according to the customer's requirement, we sent new samples to the customer, 

the customer raised several new issues, these issues were not raised before we made the change, we made the change 

again and again, 5 times, finally the customer was satisfied.