Our RSV-Z2600 cases arrived in thick cardboard, but they were not double boxed. As you can see, our box had a bit of damage. For review purposes, this works out really well as we can see how the package contents survived the UPS experience.
Everything worked out really well, and our case was untouched thanks to the dense closed cell foam. The case is more than an inch away from the sides of the box, and the packaging is around 2.5 inches thick at the corners.
Inside, we found a box of accessories. It included a paper user manual, screws for mounting components, and a mini speaker for the motherboard beep codes.