The VELUX Insulation Collar with Underfelt Collar, measuring 134 x 98cm, is an essential accessory for your VELUX roof window. This product ensures optimal energy efficiency by preventing heat loss around the window frame. Its designed to fit snugly around your window and includes an underfelt collar for additional insulation and seamless integration with roofing materials. Easy to install, this insulation collar is compatible with all standard VELUX roof windows of the same size.