You can't compare the Twist T-Shirt to cotton. It's like debating gas station black coffee and an Italian cappuccino. Made of Weightless Wool, this shirt stays cool on the hottest days and looks stylish while doing it thanks to the moisture managing properties of Merino wool. A nylon core is wrapped with wool to create a hardy fiber without bulk or weight. Weightless Wool is designed to be softer, more durable and lighter than synthetic workout fabrics. A perfect fabric when used alone for warmer days of aerobic work or layered to add warmth in colder activity. 145g/m2. 87% Merino, 13% Nylon. The lightest weight Merino t-shirt. Semi-Fit. V-neck with twist detail at center front. Set in short sleeves.