mcSquares Stickies are dry-erase, adhesive-free stickers that can be reused up to 2,000 times; a replacement for paper sticky notes. You can use any marker suitable for dry-erase surfaces on your mcSquare Stickie including dry-erase markers, dry-erase crayons wet-erase markers and wet-erase chalk pens! mcSquares Stickies will stick to any smooth surface like windows, mirrors, fridges, laptops, whiteboards, smooth walls, or cabinets. They feature a high-quality dry-erase front and aerospace grade, Bubble-Bond Tape on the back. When they get dirty just wash them off with water and they will stick just like new!