Corebond FR contains 50–60% recycled content and can be helpful in obtaining LEED certifications. This UL263 Listed (Design X860) and UL1709 Listed (Design XR746), 100 to 120 pounds per cubic foot (pcf) density material contains fire resistant microfiber to resist cracking during seismic events or shipping and handling of coated members. This fiber, combined with an early and final compressive strength greater than that in any other cementitious fireproofing material, makes Corebond FR the material of choice. Corebond FR contains no Portland cement and consequently has none of the weaknesses of conventional cementitious fireproofing materials, including resistance to extreme heat and cold and salt water spray. Corebond FR has an elevated resistance to acids, solvents, chlorides, and sulfates.