From their announcement:
Chapterhouse Studios does it again, after numerous request for Xenomorph-like alien heads for 28mm models, they release this 6 piece set.
The Xenomorph Head set is comprised of 2 resin variants in multiples of 6. The heads fit well on the current ‘Nid line-up of Warriors, Gaunts and Stealers.
These and other unique conversion kits brought to you by Chapterhouse Studios