Genuine Therma-Tru® sills and bottomsweeps help form a tight seal against wind-driven moisture infiltration at the bottom of the door system and help channel moisture away from the home. The sill pan (recommended) adds an extra layer of protection to help keep moisture away from the subfloor. Extra thick, continuous moisture- and insect-resistant all-composite substrate provides a solid stepping surface and superior rot resistance. Thick, through-colored moisture- and insect-resistant composite cap and nosing resists wear and rot, and features a wood-grained appearance. High-dam, narrow cap mates with the dual-bulb bottom sweep to help deflect moisture away from the cap; engineered U-shaped weather seal creates an added barrier against wind-driven moisture infiltration. Flush-fitting, premium stainless steel screws form an uninterrupted sealing surface, resist corrosion, and adjust the cap vertically to help maintain a tight seal over time. Thick, 15-gauge aluminum approach provides excellent durability and a solid stepping surface.