The Alpha knee sleeve uses a breathable perforated neoprene with air plush lining for the front section while the back side uses a dual layer of soft Lycra for extra comfort. To keep them super slim and flexible we use EVA foam padding to protect your knees from impact. This year we also added a Sharkskin neoprene gripper to keep the pad firmly in place. Features Breathable perforated neoprene with air plush lining, back side with dual layer Lycra and EVA foam padding.