This is the firmest tier, and it is not a starting point. 30-40 mmHg is prescription-strength compression — the level a doctor or vascular specialist specifies after examining your legs, usually for advanced venous disease, significant lymphoedema, or after a clot.
We sell it because people who have been prescribed it need somewhere to buy it. We are not going to pretend it is an everyday sock.
Read this before ordering
- If nobody has told you to wear 30-40 mmHg, you probably want 15-20 or 20-30 instead. Both are on this site.
- Do not wear this level if you have peripheral arterial disease, reduced sensation in your feet, or uncontrolled diabetes without explicit medical clearance. On a leg with poor arterial flow, compression this firm can restrict circulation rather than help it.
- Measure your ankle and calf and check them against the size chart. At this strength, a poor fit is not just uncomfortable — it concentrates pressure in the wrong place.
What it is
Graduated knee-high compression, firmest at the ankle, easing toward the knee.