Discover Teacher Created Resources® Dry Erase Pens & Microfiber Towels, 3 Packs of 15 at michaels.com. Write on any dry erase surface and wipe off easily with microfiber towels cleans better than standard whiteboard erasers. Towels measure 4-1/2" x 4-1/2". Sold as 3 sets for a total of 15 pens and 15 towels.