Rock salt ideal to de-ice walkways and driveways. Effective down to +5 degrees Fahrenheit/-15 degrees Celsius. When used as directed, safe on air-entrained, cold weather concrete that is at least one year old. Made up of 100% rock salt/sodium chloride. Use 1 cup (10 ounces) of ice melt per square yard and spread evenly, avoiding piling or overspreading. Remove resulting slush. Reapply ice melt as needed.