USPS Tracking - Package and EMS Tracking USA | Postal Ninja
Most USPS tracking codes are 22 numbers long, arranged in groups of 4 digits. However, there are other formats, among them shipping ids that start with the letters EA, EC or CP, which indicate that the package is being mailed overseas.. The first four or five digits (for domestic shipping options) and two letters (for the international ones) indicate the type of mail service you're using.
DA: 37 PA: 55 MOZ Rank: 3