Safe Step 4300 Dual Blend Blue melts ice fast with a quality blend of sodium chloride and magnesium chloride. Product is Blue in color. All deicers can accelerate surface damage to concrete, since they increase the number of freeze-thaw cycles. Poor quality concrete is especially susceptible to damage. However, the hazards associated with slippery surfaces must be weighed against the potential of surface damage. Use this product only on good quality, air-entrained concrete for cold weather climates. Do not use on concrete that is less than one year old, has exposed aggregate, is precast, stamped, pre-stressed, chipped, cracked, spalled or weathered or on stone, brick, mortar joints or wood. Not intended for melting ice on roofs, gutters or in downspouts.