Innovative 3M adhesive technology holds strongly: 4 sets of Medium Picture Hanging Strips hold up to 5.4kg in weight. The hassle-free way to hang pictures. No need for nails or screws. Strips lock into position making it easy to unlock; straighten and reposition wonky frames. Suitable for most smooth surfaces including painted walls; tiles; metal and wood. See usage instructions. Wait one hour between mounting the strips to the wall and hanging the frame. Not suitable for use on wallpaper