The Rab Powerstretch Zip Top, the PowerstretchÂ® fabric is a 4 way stretch, high wicking fabric designed for active sports. It has a close fitting, quick drying, wind and abrasion resistant pull-on designed for active users. The flat seams and smooth outer face allow for easy layering, and the thumb loops and longer sleeves give added protection when climbing, running or biking. The stretchy nature of the fabric means sleeves can easily be rolled up, and the deep front zip offers great venting options should the temperature or exertion level rise. This is an ideal mid layer or can be used as a base layer next to the skin in cooler conditions. The deep front zip and zipped front pocket also make the PS Zip Top a practical top and alternative to a standard fleece for day to day usage.