This was one of those models that I liked the idea of. If you have ever seen the special edition of ALIENS, you will remember that the Colonial Marines used automated sentry guns to defend the colony from the aliens. I am pretty confident that these models are inspired by that film. I also liked the Tarantula sentry guns that were once available from Forge World.
In the pack you get two identical sprues that allow you to build two turrets mounted with twin grenade launchers, and two with twin heavy stubbers. It also includes ammo crates and control consoles. The models go together quite easily.
As is the case with many Games Workshop models there are a number of parts, some quite fiddly. Next stage will be a white undercoat.