I didn't know they had a Flate Rate also to Canada and overseas!
• Flat Rate Boxes can be used for both domestic and international shipping:
— Available to anywhere in the U.S. for $8.95
— One rate to Canada and Mexico for $23.00
— One rate to all other countries for $37.00
*20 pound maximum for international shipments
• The inside dimensions for the two boxes available are 11" x 8.5" x 5.5" and 13.625" x 11.875" x 3.375".