30–40 mmHg compression offers extra-firm graduated pressure intended for advanced compression needs and clinical use cases. This level is commonly used under medical guidance for severe venous insufficiency, significant edema, lymphedema management, or chronic circulation disorders. It is also prescribed in certain post-surgical recovery plans where maximum compression support is required. Due to the higher pressure, 30–40 mmHg compression can be more challenging to put on and should be selected carefully, often with professional input, to ensure proper fit and safe use.