U-Pack's Tuck-in-Flap boxes with double sidewalls and extra locking flap on lid panel are extremely sturdy and safe as e-commerce boxes online. They ship flat and are quick and easy to construct manually without glue or staples. These boxes are used for a variety of application ranging from gift kits, baby products, electronics, cosmetics, mobile boxes and more. UPack stocks these in various sizes in natural brown and white kraft paper.