Black Diamond has developed a light performance T-shirt made from Australian Merino wool, in partnership with The Woolmark Company. The T-shirt, which is called Rhythm Tee, is the first product from Black Diamond's new SolutionWool layering system. The collection uses Nuyarn, an ultralight and stretchy baselayer designed for high output activities. The Nuyarn fabric is obtained by wrapping a superfine Merino wool yarn around a nylon core. The resulting fabric is said to enhance the wool's natural performance while drying five times faster. It has 35 percent more stretch and is 47 percent stronger. Black Diamond's SolutionWool layers are debuting this spring and will expand into the autumn 2019 product line.