There are various terms for helmets that are molded in one single operation where the outer shell is bonded to the expanding foam. Some are copyrighted. We use molded in the shell, a generic term.
Manufacturers seem to have as many descriptions for the process as there are terms.
We find many of them confusing, so we put up this page. Beads of polystyrene are then added to the mold, it is sealed and then injected with steam under pressure. The steam expands the polystyrene beads, forming them into the shape of the mold, essentially a completed helmet. It not only adheres to the foam, but leaves no gaps, filling every available bit of space with foam. If all other things are equal, this process can produce a helmet with superior strength.