Pumice is a light, porous volcanic rock that forms during eruptions. Its unique network of gas bubbles frozen amidst volcanic glass and minerals resemble a grey sponge. Each KHW pumice stone is 2 3/4" X 1 1/2" X 3/4" and comes individually wrapped. To use simply soak your feet (or other rough or calloused skin area) for 5 or 10 minutes, wet the pumice stone and gently rub the stone over the rough and calloused area(s) using a gentle pressure. Take care not to remove too much surface skin. For best results, follow this procedure with our Foot Balm.