The 30 mil dry erase shelf label magnets are approximately 50% stronger than the 20 mil shelf labels. The 30 mil shelf label magnets offer a thicker size for easy removal. Choose from 5 different colors: green, orange, red, white and yellow. The write on – wipe off surface allows for easy cleanup when changing the labels and eliminates the need for adhesive labels that leave a sticky residue behind. The 30 mil shelf labels are also available in 5 different lengths.