Perform your best wearing the Zone Long Sleeve Half Zip Baselayer. This tee features the BodyfitZone construction that is made from stretch merino wool and Lycra. It has strategically-placed merino mesh panels that offer breathability at all times. This lightweight jacket has mesh panels that regulate your body temperature to keep you comfortable. It has gusseted side panels that let you move your arms freely. To eliminate chafing, this tee has flatlock seams.