These are nominally 10mm figures, but these are aliens, so what's a few millimetres here and there.
In the £12 pack you get 1 Queen (22mm high), 20 Medium creatures (15mm high for the more upright ones) and 10 Small creatures (about 8mm high) and a bunch of egg clusters and face huggers.
Here is a bunch of small aliens menacing a pair of GZG's UNSC troopers. Also an open egg case and face hugger lurking ready to strike.
"That's it man, game over man, game over!"
And finally the large aliens, these tower over the UNSC figures as they come forward with a terrifying "I'm a little teapot" pose.
When these are done I'll have more than enough aliens to do the Bugs in the Reactor scenario in Tomorrow's War. Watch out Colonial Marines! Insert Aliens quote here!