The Louis Garneau Arm Warmers feature HeatMaxx fabric that has a soft brushed inside to wick moisture while retaining heat. The biceps silicone grippers hold these warmers in place yet they're easily removed and stashed in a pocket or pack when things warm up. . . . HeatMaxx: 4-way stretch opaque construction knit with brushed back. . Biceps silicone grippers. . Flatlock seams. . Reflective accents. . UPF/SPF 50. . Imported. .