Ultra-comfy underwear bottoms for everyday wear, the Siren Hipkini features lightweight 150gm corespun merino jersey fabric that’s durable, stretchy, and incredibly soft The low-profile elastic waist and leg openings offer a great fit, and the low-profile side seams maximize comfort Merino Corespun - durable merino blend regulates body temperature in all weather conditions Inspired by nature, icebreaker harnesses the performance qualities of natural fibers to offer an alternative to clothing based on petrochemical synthetics Merino is an annually renewable fiber that naturally resists odors, keeps you cool when it’s hot and warm when it’s not, and lets your skin breathe for comfort all day, every day