Our Extra Protection Running sock was created as a lighter more ventilated version of the iconic Maximum Protection Mini Crew sock with PTFE yarns strategically placed only on the bottom of the foot rather than encompassing the entire foot like it's Maximum Protection sibling. Prevents foot blisters during marathons and long-distance runs, as well as protect runners prone to getting foot blisters at lower mileages. Runners switching from conventional wicking fiber socks to wearing Extra Protection Running socks can run blister-free, lowering times and increasing mileage.