KEEP YOUR ARM WARM: ROCKBROS cycling thermal sleeves made of thicken material, Thermal arm warmers they keep the arms very warm while cycling running gym or outwork in autumn or cold winter. This will be sweet gifts for your dear friends or family. HIGH ELASTICITY & SUPER STRETCHY: Our winter arm warmer is made of nylon & spandex, the fabric is high stretchy, making the sleeves easy to put on and remove. They can machine washable, used for a long time still keep strong elastic. Beside, there are there sizes to choose, Please choose your suitable size according to measurement your arm circumference. UPGRADE PART: We add highly elastic band which Inline anti-slip high-quality silicone in order to fits tight on the upper arm long time. This arm sleeves with thumb holes design, covers the wrist and part of the palm well, fully keep arm warm. the reflective part is very helpful in low light riding. ABSORBSWEAT & BREATHABLE: Comfortable and delicate Thermal fleece lining retains arms heat, fabric that has a soft brushed inside to wick moisture while retaining heat. WORRY FREE GUARANTEE - We offer a 100% satisfaction guarantee. If the arm warms are Wrong size or damaged within 90 days, will replace it for you or provide a full refund so can feel confident purchasing with ROCKBROS.