Flat Rate is Pricing not Thickness
Flat Rate Priority Envelopes… Is it Flat Rate Pricing or does it mean it has to be Flat?
Flat Rate Priority Envelopes means it is the same price to mail a package anywhere in the United States, Puerto Rico and Territories including FPO/APO for around $5.00
It can be any thickness as long as the envelope has not be reshaped by cutting it … actually read the DMM here
This is 123 1.5 of the DMM for USPS.
If it fits, it ships. Â UP TO 70 lbs.
You can print off the DMM from the USPS website. Â Copy 123 1.5 and take to the post office if you have postal clerks that don’t know the postal regulations.