A simple slit in the larger circles of this sticker collection let you relay messages, store lists, hold CDs, you name it. The stickers themselves are completely removable but hold fast when on a clean, dry and flat surface. This sticker collection also has a modern design that is perfect in the kids room as well as a modern home office.These stickers will work on just about any surface, but take care with wallpaper or some delicate surfaces. If in doubt, test in an inconspicuous place prior to applying all the stickers. Also, wait 10 to 15 days after painting before using stickers. Though the paint feels dry, it needs adequate time to cure. As with any adhesive product, these will work much better on clean surfaces free of dust and the like. Specifically, they will work well on surfaces including but not limited to walls, mirrors, your fridge, laptop covers, tile, glass, lockers, furniture, and automotive surfaces.Please note this product does not ship to Pennsylvania.