Louis Garneau's Arm Warmers 2 are crafted from Garneau's HeatMaxx nylon/spandex material with soft brushed insides for optimal moisture transfer and heat retention. You'll also appreciate the comfy flatlock seams, bicep grippers to keep them in place, UPF 50 sun protection, and reflective accents for enhanced visibility. And, when you warm up, these warmers are easily stashed in a pocket or pack.