Editorial Review CoBaSi Yarn from HiKoo is a cotton, bamboo and silk blend with elastic nylon for a gentle on the hands wool-like stretch. It comes in 50 gram hanks and a wide range of colors, making it the perfect candidate for warm-weather color work. Soft and machine washable, this will be a go-to for a variety of hardy garments. The possibilities are endless, so get some CoBaSi and cast on!