Add a Layer of Options for Cold Weather Runs. Add a versatile option for cold weather runs with these arm warmers. Made from our DriLayer fabric, moisture is wicked away from skin to keep you from getting chilled, while silicone grippers at the bicep opening keep them securely in place. Plus, reflective detail helps to keep you visible in low light. Stay warm as the temperature drops with this must-have running accessory for a complete runner's wardrobe.