We do apologize for not informing you before about this request of pre-shipment sample. However, please carefully note that this is not the condition for sample approval prior goods loading. The customer just would like to make sure that SO2 is not over 100 ppm as your specification by external lab guarantee and we will be the one who is responsible for this expense. If you are confident with your SO2 result from your lab. We don’t think that this would cause any problems to your end.
Please consider this as the purpose to arrange is with the pre-shipment sample for reference and also please consider this as a good sake of marketing support. Otherwise, please you may ignore our request.