Designed specially to help blood circulation, these compression socks reduce swelling and leg fatigue while providing comfort and the added benefits of copper. Manufacturer offers unconditional guarantee. If you are not satisfied with this product, return it with a dated receipt to Aetrex Worldwide for a replacement pair or one of like value. Sizing for men: Medium fits men"s shoe size (USA) 4.5-8.5; Large fits men"s shoe size (USA) 8.5-12; Extra-Large fits men"s shoe size (USA) 12-15.