The Arc'teryx Men's Phase SL SS Crew is a baselayer for High output activity. Hike long, hard and with plenty of gusto. The Phasic; SL fabric will wick the moisture away, dry quick and keep you comfortable throughout the way. Flatlock seams won't annoy you underneath your pack and gussets at the underarms encourage natural movement. Features of the Arcteryx Men's Phase SL Short Sleeve Crew Next Gen Phasic SL fabric provides a softer touch, improved stretch and exceptional moisture management Flatlock construction improves next-to-skin comfort Crew neck line Gusseted underarms provide mobility and comfort Durable Anti Odour finish Updated style lines and improved Fit Mechanical stretch textile for unrestricted mobility Merrow stitch seam construction reduces seam size Next-to-skin Fit aids thermal efficiency and moisture transfer Anatomical shaping for Fit and comfort