The Alé Heat long sleeve base layer top is soft and warm, made of PrimaLoft Yarn fabric, with thermal memory that keeps the body warm at all times. This fabric allows for breathability and rapid expulsion of perspiration.Features:- Insulating PrimaLoft Yarn fabric, which keeps the body warm and dry at all times- Temperature range: 2º / 10º CTechnology:- PrimaLoft YarnThis insulation, made from merino wool, combines the softness and good treatment of merino wool with soft PrimaLoft fibres. Merino wool pulls moisture away from the skin, while PrimaLoft fibres wick it away to the outside to dry the inside 20% faster than merino wool alone. This means that less moisture is absorbed, body temperature is better regulated and, as a result, comfort is improved. Garments with this fabric are designed for anyone looking for good performance.