MicronWings sends international orders through the Australia Post EMS network. 
To comply with the US import tariff regulations, Australia Post has partnered with Zonos, a company which handles tariff payments to the US government on behalf of international suppliers. When your order is sent, MicronWings pays any relevant tariff and processing charges for your order directly thought the Zonos network. This ensures that when your delivery arrives in the US for customs clearance, any fees and charges will have already been paid.