From the publishers website:
COPPER DRAGON brings you high quality 2D gaming tiles at a price that won’t break your gaming budget (hey, you need that money for more miniatures, right?) Featuring texture art by industry award winning artists, each set is designed to be compatible with our other terrain offerings, allowing you to make the most of your Fat Dragon Games terrain purchases.
Basic Dungeons 1 features 24 tiles, bonus rooms and optional freestanding doors. This set is the foundation of most upcoming dungeon releases in this series, so pick yours up now!