These 2 sings are printed on 2 thin transparent plastic sheets. The designer and manufacturer of this product expects it to be laid ontop of it's plastic wallcovering and the easiest way to achieve that would probably to be use a can of 'spray mount' glue. Otherwise you could still stick them to any wall using traditional temporary methods like blue tac, sticky pads, strong double sided tape or drawing pins depending on the wall covering. Product states it is suitable for outdoor use.