Arm muscles stay warm and active with compression technology. Protects skin from abrasions. hDc Moisture Management Technology is all about cool and dry. 6-thread flat-lock technology for strength at the seams. 50+ UV skin protection. Includes one pair. Content: 80% nylon/20% spandex. Measure forearm circumference just below the elbow: S (8-9.5"), M (9.5-11"), and L (11-13").