The improved Option knee pad is completely redesigned. It features a hard molded polypropylene shell with a perforated bio-foam liner for increased breathability and superior impact protection. The reinforced TPR (Thermoplastic Rubber) hinge system ensures full coverage and comfortable knee movement. � Constructed with a hard molded polyproylene shell Perforated bio-foam liner for increased breathability Full knee to shin coverage Reinforced TPR hinge system Asymmetric design for left and right legs Sold�as a�pair One size fits most over 60" and 115 lbs.