DetailsMERGE4 Sock Size Chart These black skull socks are part of MERGE4's Essentials collection - not-so-basic socks for everyday life. Dreamy colors, high quality design and ultimate comfort for skate socks like no other. MERGE4 socks are designed with gradient pressure technology, meaning gradual compression starts at the ankle and goes up the leg. This ensures maximum comfort and effectiveness, boosting circulation and increasing healthy blood flow. At a light, non-medical level of 15-20 mmHg compression these socks are designed for everyday wear and situations, from lounging to working out or hopping on a flight to flying down a mountain bike trail!