The primary body of the strap is a soft nylon/foam laminate with contact closures.. A cylindrical Floam™ bladder is encased inside the body of the primary patella strap and may be adjusted for added compression.. Floam is a material that provides uniform compression and a customized fit while prohibiting pressure from being displaced to bony prominences.. Medium is for 13 – 15 inch knee circumference (measurement taken at just below kneecap)..