If your mail is a 1/4″ thick or less it must meet the following requirements:
- Must be a rectangle.
- Must be at least 3-1/4″ tall.
- Must be at least 5″ wide.
If your envelope is smaller than 4-1/4″ high and 6″ wide, it must be at least .007″ thick.
If your envelope is larger than 4-1/4″ high and 6″ wide, it must be at least .009″ thick.
