T/T advance payment is required for some high-value samples (see our samples ordering policy) and small quantity order shipped by air.To the customers who have long-standing business relationships with us, we send free samples; and for the small quantity order, document against payment is used.It takes 3-4 days for us to received the wire transfer made from anywhere in the world.An irrevocable Letter of Credit is also an often used payment method. It is often referred to an L/C. Letters of Credit are formal payment methods that offer a lot of protection to the parties.Simply put, a letter of credit is a letter written by the importer&＃39;s bank to the exporter. It verifies that the payment will be guaranteed when the bank is presented with the concrete documents (bill of lading, and freight documents). Most letters of credit are "irrevocable" once the importer has had them sent. To our customers who have long-standing relationships with us, for larger quantity order shipped by sea, we usually make the payment arrangement as 50% made via T/T advance payment and 50% made via D/P(document against payment) to expedite the whole transaction process.