2 tone lightweight fleece mid-layer with plenty of stretch for cold weather activities. Constructed using a double knitted fabric, the Rab Nucleus is a comfy, stretchy, light layer ideal for walkers and climbers. In the depths of winter, the Nucleus works well as a base layer next to the skin too. The Polygiene Stay Fresh Odour Control Treatment ensures you stay smelling fresh and can stay out and play for longer. This pull-on had a deep venting YKK zip and chin guard and the collar is nice and high for added protection against the chill.