Innovative 3M adhesive technology holds strongly: 4 sets of Medium Picture Hanging Strips hold up to 7.2kg in weight. The hassle-free way to hang pictures. No need for nails or screws .Strips remove cleanly without leaving holes, marks or sticky residue. 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