Maximum size for Yu-Packet! A4 cardboard boxes, perfect for Yu-Packet Post, 10 sheets ★These cardboard boxes can be used as packing materials for Click Post, Yu-Packet (Post), Yu-Pack, and Takkyubin 60 size. Within the standard size for non-standard mail. Size: Inner dimensions - Length 33.2cm x Width 23cm x Thickness 2.6cm Outer dimensions - Length 33.5cm x Width 23.4cm x Thickness 2.9cm Thickness - 1.1mm Total of the three outer dimensions - 60 cm Color: Brown *Will be folded and shipped in a delivery vinyl bag. *Please note that the shorter side will be folded in the opposite direction. *If assembled with the front and back reversed, it may exceed the regulations of the mail service you are using. *Please be aware that due to the nature of paper products, there may be corner bends, dents, wrinkles, etc. upon delivery and during shipping.