The VELUX Insulation Collar with Underfelt Collar 78 X 118cm is designed to enhance the energy efficiency of your home by limiting heat loss through your roof window. Made from durable materials, it ensures a tight seal between the roof window and the roof structure. This insulation collar comes with an underfelt collar for additional protection against weather elements, providing a superior barrier against wind and rain. Its an essential accessory for VELUX windows, offering you peace of mind and contributing significantly to a comfortable indoor climate.