Double boxing in a haphazared manner is not as good as packing it with
proper packing material in a single box. Generally, the original box and
packing is designed to transfer the stress to the item shipped without
damage.

I have received packages that were double boxed, but the packing material
was simply foam pellets with very little spacing. Foam pellets can shift,
or the box can be torn with damange to the contents.

Rigid foam that is form fitted is excellent. Damage is often the result of
mass times acceleration. What packing tries to accomplish is reduce
acceleration - or decelleration.

An SB-220 wrapped in a pair of old pants, or a Johnson Ranger in a
grapefruit box and a banana box with no packing material is not adequate.

Colin K7FM