DAMAGE-FREE PICTURE HANGERS: Includes 28 Pairs, 56 Strips of White Command Medium 10 lb Narrow Picture Hanging Strips, unique hassle free wall hangers for hanging pictures without nails or damage. WORKS ON A VARIETY OF SMOOTH SURFACES: Wall hanging strips work on a variety of smooth surfaces, including painted walls, finished wood, painted concrete cinder blocks, laminate, glass, metal and tiles SURFACE PREP: Clean the desired surface with rubbing alcohol to remove grime and dust to allow the no damage wall hangers to bond to the surface; the indoor temperature must be between 50 degrees Fahrenheit and 105 degrees Fahrenheit USAGE TIPS: Wait seven days after painting before using the Command Picture Hangers to allow paint to cure; do not hang over beds or on wallpaper; do not use the wall hanging strips to hang valuable items EASY CLEAN REMOVAL: Lightly hold the top of the removable adhesive strips and slowly pull straight down towards the floor to remove and prevent damage of walls and surfaces