This upgrade fee is in addition to the $5 flat rate and would increase your shipping speed from First Class (2-5 business days) to Priority Mail (1-3 business days). It does not guarantee delivery, but these are the descriptions according to USPS.
This upgrade fee is in addition to the $5 flat rate and would increase your shipping speed from First Class (2-5 business days) to Priority Mail (1-3 business days). It does not guarantee delivery, but these are the descriptions according to USPS.