They are real beermats, that I've had printed with grids to make them also great as gaming aids. One side is printed with a 10x10 9mm grid, that is perfect for drawing dungeon geomorphs on. The other side has a 3x3 29mm grid, that is ideal for use with miniatures.
The beermats have a 3mm white border. Once trimmed they can be place next to each other for seamless maps and battlemats. The beermats may also be cut up to make floorplans. The picture of a floorplan at the bottom of the page shows what you can do with just 12 beermats.
There are only a limited quantity of these available as this is really just a test. If they are popular then I'll consider doing more.
Links to the different pack sizes are here:
Pack of 12 £2.00
Pack of 24 £3.90
Pack of 48 £7.50
Pack of 125 £18.00