The Smartwool PhD Run Light Elite Micro Socks are highly recommended for women's ultrarunning. These socks are made with a blend of merino wool and synthetic fibers, providing excellent moisture management and temperature regulation. The light cushioning offers impact protection without adding bulk. The micro length is perfect for those who prefer a shorter sock. These socks also feature a 4 Degree Elite Fit System for a secure and comfortable fit. With their superior performance and durability, the Smartwool PhD Run Light Elite Micro Socks are a top choice for ultrarunners.