Northwave sonic winter socksthese sonic winter socks from northwave are made of isolwool a combination of merino wool and meraklon polypropylene and provides 5 times the abrasion resistance compared to socks made of 100 wool and also provides exceptional thermal insulation lightweight added comfortthey are extremely lightweight for winter socks weighing only 25g and have 17cm cuffs these winter socks also have elastic tops to prevent slippage and reinforced toes and heels for durability and