Designed to fight the cold - The adidas by Stella McCartney Run Neck Warmer is built from fleece to help protect you on cold weather runs. Bungee-adjustable.ADIDAS by STELLA McCARTNEY Collars. Designed to fight the cold - The adidas by Stella McCartney Run Neck Warmer is built from fleece to help protect you on cold weather runs. Bungee-adjustable. 100% Polyester