These travertine stone tiles are heat, water and weather resistant, so they can be used indoors or out, for coasters or trivets, wall decor, garden art, etc. The 4" x 4" coasters have a cork backing to protect table surfaces; the 6" x 6" trivets have rubber feet to protect countertops as well as a hole on the back for hanging. The decorations are not decals, but are permanent images on stone. Because travertine is a natural stone product, each tile will be unique.