The Skyfol XT series is a selection of high performance and durable exterior window films, the most widely used architectural film types in Europe. The XTS series is a reflective, metallized film, offering the highest heat rejection.The Skyfol XT series is a selection of high performance and durable exterior window films, the most widely used architectural film types in Europe. The XTS series is a reflective, metallized film, offering the highest heat rejection.