CRL 888 premium grade caulking compound consists of a butyl based formula that is economical, repels weather extremes and will last for many years. Voids can be filled in up to 3/8” when applied to a variety of woods, metals, glass, concrete and plastics. This all weather caulking compound contains a unique ultraviolet fighting formula that provides outstanding longevity and will not crack or harden over the years. CRL Premium Grade Caulking Compound is recommended for both interior and exterior applications and can be applied to thresholds, aluminum siding, between metal building panels, vehicle body joints and many other areas. Apply in temperatures between 40 and 120ºF. The service temperature range is between -20 and 200ºF.