Ivanhoe Compression Socks are specialized hosiery, designed to help prevent the occurrence of, and guard against further progression of venous disorder such as edema, phlebitis and thrombosis. There are 4 main compression levels which are measured in millimeters of mercury (mmHg). The higher the numbers, the higher the compression. Our compression socks are Class 1 compression. 15-21 mm Hg, “support” socks, flight socks, sport compression socks.