Please note this is for a recessed installation. Insulation collar - BDX • Insulates around the roof window frame, reducing heat loss and eliminating cold bridges. • Makes insulating and installing the window a simple process. • Click fittings ensure a fast and accurate assembly. • Comes with an underfelt collar - BFX. Underfelt collar - BFX • Ensures a weather-tight seal between the roof window and the roof. • Pleated material ensures a flexible and tight seal to the underfelt of the roof, whatever it's construction. • Made from diffusion open material to minimise the risk of condensation. • Comes with transverse drainage gutter to lead water away from the head of the window if a tile or slate is broken above the window. • Welded corners ensure a watertight and simple installation.