Fusion cup sleeve is made of a functional very soft and stretchy material. The fabric, that is made with 37.5 technology always aims at keeping your body temperature at 37.5 degrees which is your ultimate comfort zone where you perform at peak level. Reflective prints and small ventilation holes at shoulders gives a very sporty design. UV protection is built into the 37.5 technology and protects you from the sun, it will never wash out. You have to experience it yourself to understand the difference.