From the publisher's website:
The Blueprints product line offers you old-fashioned blue printed maps for using in your adventures and campaigns. For each map you get a blueprint version and a standard black and white version. The maps are all vector-based so you will get maximum print resolution. Despite their old fashioned appearance each map offers you a degree of customization, using the pdf technology at its best. A button (which will not be printed) on each map allows you to turn on and off the grid, eliminate the room numbers, get the walls filled, don’t show doors and furniture and many other options, depending on the kind of map.
Each product features a classic fantasy adventure location: a dungeon, a keep, a temple complex, a thieves guild and so on. You can use these map as reference to build your own adventures or simply take them at hand in case your players go in an unexpected direction during the campaign.
While offering you the best quality, these products are really inexpensive.