SSTM-T11-BLK_Small j-M Tesla Men's Cool Dry Compression Baselayer Mock Long Sleeve T Shirts T11 Coolgear shirts&pants are designed for all seasons (not for Warmth) Find your size on the chart below. If you prefer a looser fit, go up a size. 87% polyester-13% spandex. Excellent elasticity with enhanced range of motion. Perfect option during various indoor activities and outdoor excursion. Moisture Sensing/Quick time Dry/TWO-WAY Air Circulation.