Editorial Review How It Works: Offers support and stabilization to reduce likelihood of further strain or tearing. Therapeutic warmth will increase flexibility of muscle. Design Theory: Neoprene sleeve provides snug fit, providing effective support while staying in place. Sizes: Small 16 - 18" Medium 18 - 20" Large 20 - 22" XLarge 22 - 24" (Measure circumference 6" above patella)