The Mueller Streamline FB214 09 25 is a high-performance silver double ply black poly product with an R-value of 4.2. This insulation material is designed for optimal thermal efficiency, making it ideal for various applications in HVAC systems. Constructed from durable black polyethylene, it offers excellent resistance to moisture and environmental factors. With dimensions tailored for versatility, this product ensures a snug fit in standard installations. The FB214 series complies with industry standards, ensuring reliability and safety in performance. Perfect for both residential and commercial use, it provides superior insulation to enhance energy efficiency.