Safe Step Pro Plus offers the convenience of high-visibility crystals and powerful magnesium chloride/sodium chloride mix for an efficient, ice melt. The blue crystals are easy to see. They melt ice and snow down to negative 7 degrees Fahrenheit (negative 21 degrees Celsius). It is made of 100 percent rock salt and with a unique screening process for optimum-sized crystal for improved melting performance. It is fast, reliable and proven effective in clearing the way of ice and snow. Cost-effective ice melter is safe for people, pets and the environment.Safe Step Pro Plus offers the convenience of high-visibility crystals and powerful magnesium chloride/sodium chloride mix for an efficient, ice melt. The blue crystals are easy to see. They melt ice and snow down to negative 7 degrees Fahrenheit (negative 21 degrees Celsius). It is made of 100 percent rock salt and with a unique screening process for optimum-sized crystal for improved melting performance. It is fast, reliable and proven effective in clearing the way of ice and snow. Cost-effective ice melter is safe for people, pets and the environment.