What guarantee do we have since advance payment is required?

We are Not aim to to do once-business. We are going to build strong and long term relationship with all of ourclients . Our success is based on customers' satisfaction. Further, each order has a SOP (Standard Operation Procedure) to follow.  Production is only proceeded after all details have been confirmed.  We do 100% inspected before shipment, and take responsibility for default goes beyond acceptance.