Effective down to +5 degree Fahrenheit/-15 degree Celsius. Made up of 100 percent rock salt/sodium chloride. Use 1 cup (10 ounces) of ice melt per square yard and spread evenly, avoiding piling or overspreading. Simple and proven effective Unique screening process for optimum-sized crystals Safe when used as directed on air-entrained cold weather concrete that is at least one year old Safer on air-entrained, cold weather concrete that is at least one year old when used as directed