The VELUX Insulation Collar with Underfelt Collar is an essential accessory for any VELUX roof window installation. It significantly enhances the thermal efficiency of your window, ensuring minimal heat loss and reducing energy costs. This product also serves as a barrier against underfelt intrusion, conforming to the shape of your window for a perfect fit. It measures 114 x 118 cm, making it suitable for a wide range of window sizes. Made from durable materials, its designed to withstand harsh weather conditions and provide long-lasting performance.