From publisher blurb:
The Colony 19 product range provides a number of sci-fi/near-future floor tiles that are suitable for use in most RPG's and wargames of that genre. The tiles themselves are scaled at 1" per grid square, and are intended for use with 28/32mm miniatures.
As the name implies, this particular set contains twelve pages of tiles that can be used to represent areas that have become 'infested' with alien organisms. In addition, the set also introduces narrow (1 square wide) passages to the Colony 19 range - in both 'normal' and 'infested' states (to maximise their usage).
Note: to make full use of this product you will also need the Colony 19 starter set.