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.
