McDavid Patella Knee Support With Stays Black 421 This support features two medial and two lateral spring steel stays, lends minor ligament support and helps relieve the symptoms of Chondromalacia, patellar subluxtion and patellar tendinitis. Long 4 mm thick neoprene sleeve with nylon facing on both sides. Neoprene patella knee support with padded buttress design. Two spring steal stays on medial-lateral sides for ligament support. Open-patella in the front. 3/16" thick 100% latex free neoprene with an outer nylon covering for greater durability. Two circumferential straps on the top and bottom for additional compression and a snug fit. Provides Level 2 support and protection. Sizes: Small, Medium, Large, XLarge, 2XL - See our sizing chart tab above for important sizing guidelines. Model: McDavid 421. Black.