It has a long deep venting half zip to give you a breather when working hard and has a chin guard to avoid irritation. Also incorporated into the fabric for the lifetime of the garment is Polygiene Odour Control Technology. It is natural, long lasting and ideal for when on extended trips when laundering is not possible. At approximately 40g the Interval can be worn by itself or as a baselayer under a fleece on cooler trips. The Interval also has a UPF 35+ sun protection factor as an added bonus.