STYROFOAM™ Brand CAVITYMATE™ Ultra Insulation is a durable, moisture-resistant or lightweight extruded polystyrene foam board specifically designed for use in wet cavity wall environments. Manufactured with a patented carbon black technology, STYROFOAM™ Brand CAVITYMATE™ it features an "R-value" of 5.6 per inch (RSI of 0.97 per 25 mm), the highest of all extruded polystyrene foam insulation products. Its closed cell structure provides advanced long-term thermal performance & moisture control. Sized to fit snugly between wall ties, it can also save time and money on the job site.