Arm warmers are clothing accessories designed to keep the arms warm while allowing for flexibility and ease of movement. They are typically made from stretchy materials like spandex or wool and can be worn over short-sleeved shirts or under jackets. These garments are popular among athletes, especially cyclists and runners, as they provide warmth during cool weather without the bulk of long sleeves. Arm warmers can easily be removed and stored when temperatures rise, making them a practical choice for outdoor activities.