Pro-Tec Gel Force Knee Support is great for alleviating knee pain and providing moderate knee joint stability. It provides patellar (knee cap) stability with compression surrounding patella. Offers stability on medial and lateral sides of knee. Breathable, soft fabric offers 4 way stretch applying even, comfortable compression throughout brace. Thick oval gel provides excellent comfort and support to patellar (knee cap) area. Medial (inside) and lateral (outside) spiral stays offer overall knee joint stability. SPECIFICATIONS Sizes: Circumference measured 1” above top of patella Small (13” – 14”) Medium (14” – 16") Large (16” – 18”) X-Large (18” – 20")