Thermal tops are clothing items designed to provide warmth and insulation, typically made from materials like polyester or wool. They are often worn as base layers during cold weather activities, such as skiing or hiking, to help retain body heat while allowing moisture to escape. These tops come in various styles, including long-sleeve and short-sleeve options, and can be worn alone or under other garments. Many thermal tops feature technologies that enhance their performance, such as moisture-wicking properties, which help keep the wearer dry and comfortable during physical activities.