Mount Pro Stretch Jacket Jacket with the benefits of maximum stretch The Mount Pro Stretch jacket is made from the renowned Polartec Classic 100 material. The extra stretch construction gives you flexibility and room to move when outdoors or at sea and with practical and roomy side pockets, and rubber zipper pulls - this is a great jacket for the colder months of the year.Polartec Classic 100 Construction to give you great comfort, warmth and durabilityFull stretch fabric giving you a superb fitSide pockets and Rubber zipper pulls for ease of access and to help keep your hands warm in cold weather. What is Polartec Polartec is a range of high-performance, lightweight knit fleece fabrics that give you warmth, durability and lasting value for performance at a high level.