Broan RDH is a radiation damper designed for use in 1, 2, or 3-hour rated floor-ceiling and roof-ceiling assemblies. It is compatible with specific Broan and NuTone fan models. The damper prevents the spread of fire and smoke through ventilation systems by automatically closing when exposed to high temperatures. It features a fusible link that melts at 165°F, triggering the damper's closure. The RDH is easy to install and comes with a housing mask to protect it during construction. It includes a metal grille for a clean and finished appearance.