It is a lightweight top with flat locked low bulk seams for optimum comfort and a nice long zip for extra ventilation with chin guard to avoid irritation. Also incorporated into the fabric for the lifetime of the garment is Polygiene Odour Control Technology. Its natural, long lasting and will keep you feeling fresh all day. At approximately 40g, the interval can be worn by itself for multi activities or as a baselayer in the cooler months. Also it has a UPF 35+ sun protection factor as an added bonus.