This most affordable international shipping option (Small Packet Air) does not include tracking. Once the package is dropped off at the local post office, there is no way to locate the shipment until it arrives at your address.
So far, this service has been quite reliable. In almost 2000 shipments, only two have had to be resent.
There have been shipments that have encountered significant delays. This appears to be most commonly due to customs issues, which are difficult to predict. If your order does not come within the estimate time-frame, please submit an order support request.