Easy to Assemble: These small shipping boxes are assembled in seconds without tape, glue, or staples. Please refer to the guidance in the video or images. Crush Resistant: Compared with the traditional design, high-quality corrugated cardboard with slots makes the rectangular mailing boxes RELIABLE AND STURDY, and the standard 90°angles will protect the items inside. Widely Used: Recyclable 12 x 9 x 4 shipping box fit for mailing, packaging, and storing small and lightweight fragile items, such as books, CDs, T-shirts, hats, mugs, and so on, can meet most carrier specifications. Fine Kraft Paper Surface: No printings on the 12x9x4 cardboard boxes and great for small businesses to displaying your brand, label, and gift stickers. Gives your products that professional final touch when reaching customers. Pack of 20: All 20 kraft brown literature mailers PACKED IN A BIGGER CARTON to prevent damage during transit, and flat packing method to reduce volume and storage space. These sturdy brown mailing boxes measure 12x9x4 inches (external dimensions) and practice perfectly in small-item packing, shipping, mailing and storing.