Well, half a helmet anyway.
The top's been torn off to expose Vader's brain (which, apparently, is made from felt) to the elements.
Does it really need spelling out? It's Darth Vader, with his brain hanging out.
After all the artistic desecration, it's nice to see a helmet that at least makes passing acquaintance to the actual movies.
Even so, the way that the starkness of the image is undercut by the DIY, pulp 1950s aesthetic symbolised by the felt, is a reminder that, at heart, there's something gloriously B-movie-ish about Vader.