Some rocket packs are also encased in pyromesh. This is usually the case when buying the more powerful 1.3G rockets by mail order. The pyromesh allows the rockets to be classified as 1.4G, making storage and delivery easier (far fewer couriers take 1.3G fireworks). With rockets it is easier to spot pyromeshed items because the box will be rectangular and will rattle a lot!
For sets of larger rockets (e.g. cases of 4 and long, rectangular boxes) you should first open each small end because in many cases the cages have their own hinged cap. This can simply be unlocked by sliding open the lock, opening the lid and then pulling the rockets out.
For larger, complete cases of rockets the entire inner box will be meshed and strapped. In this case it is usually easier to remove the entire card outer and then snip the straps before removing one or both halves of the mesh cage to get to the rockets.