Woolie Boolie, 4"A DeFeet favorite, the Woolie Boolie is padded throughout the footbed and on the cuff, keeping you warm in any season without getting too hot in mild weather. This sock is available with either USA Merino wool or a blend of Merino and Repreve, a recycled performance fiber locally manufactured from recycled plastic bottles, reducing landfill waste. Wool has naturally antibacterial properties, so it takes a lot of sweaty abuse to make a Woolie Boolie