HAKUMA Men's Compression Shirt Short Sleeve for Running Fitness Workout Base Layer 8% spandex Smooth fabric provides extreme comfort and compression without restriction Perfect option during various indoor activities and outdoor excursion Stretchy and durable material grabs your muscles tightly and improves your performance Great for skiing, snowboarding, training, competing, and all weather sports and activities Find your size on the chart on the left. If you prefer a looser fit, go up a size.