![USPS Flat Rate Box Shipping Sizes and Price Breakdown - How to Enable Flat Rate Boxes on WooCommerce - ELEXtensions USPS Flat Rate Box Shipping Sizes and Price Breakdown - How to Enable Flat Rate Boxes on WooCommerce - ELEXtensions](https://cdn.elextensions.com/wp-content/uploads/2018/07/usps-flat-rate.png)
USPS Flat Rate Box Shipping Sizes and Price Breakdown - How to Enable Flat Rate Boxes on WooCommerce - ELEXtensions
![Paul Sherman on Twitter: "It is physically impossible to exceed the 70-pound domestic weight limit for a small flat rate box. The interior dimensions (8 5/8" x 5 3/8" x 1 5/8") Paul Sherman on Twitter: "It is physically impossible to exceed the 70-pound domestic weight limit for a small flat rate box. The interior dimensions (8 5/8" x 5 3/8" x 1 5/8")](https://pbs.twimg.com/media/FQ07gk4XEAAbGwF.jpg:large)
Paul Sherman on Twitter: "It is physically impossible to exceed the 70-pound domestic weight limit for a small flat rate box. The interior dimensions (8 5/8" x 5 3/8" x 1 5/8")
![Amazon.com : Foil Insulated Box Liners, 8.5" x 1.5" x 5.25" -50/Case (Fits in USPS Small Priority Flat Rate Box) : Office Products Amazon.com : Foil Insulated Box Liners, 8.5" x 1.5" x 5.25" -50/Case (Fits in USPS Small Priority Flat Rate Box) : Office Products](https://m.media-amazon.com/images/I/51b3oyS5vPL._AC_SX355_.jpg)