TruExterior Siding and Trim utilizes innovative Poly-Ash technology. This proprietary blend of polymers and fly-ash produce a product with outstanding durability, workability, and stability. Fly-ash is a by-product recovered from coal combustion. When fly-ash is combined with polymers, it becomes a durable material that’s ideally suited for exterior siding and trim. Rigorously tested in various extreme climates, TruExterior products are resistant to moisture and bugs once installed.