Many white thermal shirts use a polyester/spandex blend—commonly specified as about 90% polyester and 10% spandex.
Common necklines include crew necks and mock/turtleneck styles; some mock or extra-long mock turtlenecks include built-in gaiter coverage for extra neck protection.
They commonly list performance features such as moisture-wicking fabric, quick-drying construction, breathable mesh panels, and 4-way stretch for mobility.
Most are long-sleeve thermal tops that extend below the waist. Some styles include thumb-holes to help keep sleeves in place and provide extra hand warmth.
They are described for all-purpose outdoor and active uses such as camping, skiing, snowboarding, and running.
Care varies by product, so follow the garment label. Common instructions include machine washing and tumble drying; some listings advise washing in warm water and then hang-drying or tumble-drying on low heat to help avoid shrinkage or sagging.
Some tops are fleece-lined for added warmth, while others are form-fitting thermal base layers that rely on moisture-wicking fibers rather than a fleece interior.
They are described as low-bulk and made with spandex-based stretch so they stay in place under sweaters, jackets, or ski wear, helping to prevent bunching and binding when layered.