From the publisher's website:
Illustrated wilderness terrain tiles for use with the Dungeons & Dragons Fantasy Roleplaying Game
The Dungeon Tiles Master Sets are designed to give Dungeon Masters the tiles they need to build Dungeons & Dragons adventure maps, including maps appearing in published adventures.
With this box of customizable terrain tiles, Dungeon Masters can add new dimension to their Dungeons & Dragons tabletop experience. Easy to set up and infinitely expandable, this Dungeon Tiles set allows DMs to create the adventures they want to play.
This box contains 10 double-sided sheets of illustrated, die-cut terrain tiles printed on heavy cardstock. The tiles feature wilderness sites and terrain elements that Dungeon Masters can use to build exciting encounters set in the outdoors.