20 percent nylon or 50 percent polyester fiber or 30 percent polyurethane. Effective for PainReliefSylong elbow brace is best for all kinds of elbow injuries, injuries, elbow fractures and discomfort, such as tennis elbow, cubital tunnel syndrome. It provides comfortable support by gently fixing the elbow, keeping the elbow straight at night while sleeping. Stabilizing Support Designed with three plastic support strips, these three strips are evenly distributed on the arm, which can fix the arm effectively. To prevent the arm movement and keep the arm straight. Comfortable and lightweight The splint has soft foam as light as a feather, filling lined with breathable cotton and covered with flannel-like fabric that allows your skin to breathe, comfortable compression for your elbow. anti-drop shoulder strap To prevent the elbow splint from sliding down the elbow at night. Velcro closure can be easily adjusted with one hand for desired compression and support, fits left or right arm. 2 sizes We have two sizes for all arms. S or M for smaller arms and L or XL for larger arms. To determine the correct size, measure the circumference of the center of the biceps. The S or M size fits 10-14 inch biceps. The L or XL fits 12-16 inch biceps. measure the circumference of the center of the biceps. The S or M size fits 10-14 inch biceps. The L or XL fits 12-16 inch biceps. measure the circumference of the center of the biceps. The S or M size fits 10-14 inch biceps. The L or XL fits 12-16 inch biceps.