The Matrix 190 Zip Tee is a great mid-weight base layer that is ideal for wearing next to skin, or as a very light weight mid-layer during warmer weather. It features long sleeves & slim fit to allow for greater surface contact with the skin to aid the wicking process; a YKK zip neck closure allows for venting if you start to overheat, & the flatlocked seams help to reduce rubbing when wearing a harness or pack waist belts. The Matrix 190 Zip Tee is made from a 190g/m 2 hybrid of merino & synthetic yarns. Combining the thermal, wicking & antibacterial properties of merino wool with the quick drying & wicking features of synthetic; overall it protects against bad odours and is highly efficient at moving moisture away from your body. Basically it is a great multi-day/multi-activity piece. Slim close fit Narrow flatlocked seams YKK zip closure.