From publisher blurb:
The River Core Set is a printable dungeon floorplan compatible with any RPG/Dungeon-Crawl game. It can be used as a standalone gameboard, or combined with any same-scale tileset.
The River Core Set is a geomorphic set, comprising 6 10x10 square battlemaps which can be arranged in multiple layouts. Each component features a river surrounded by countryside/wilderness.
Also included is a set of 300dpi full size jpgs, for poster printing or VTT.